A Green Approach to Valorizing Abundant Aquatic Weeds for Nutrient-Rich Edible Paper Sheets Production in Bangladesh

Abstract

The rapid and unprecedented expansion of the global population highlights concerns about the sufficiency of food resources to sustain this growth. This study investigates and substantiates the feasibility of renewable food resources in order to meet the nutritional requirements of consumers. Three edible aquatic weeds, helencha (Enhydra fluctuans), malancha (Alternanthera philoxeroides), and kalmi (Ipomoea aquatica), were used to produce edible paper sheets. The composition of the raw aquatic weeds and paper sheet samples was analyzed, including the proximate composition, amino acid content, minerals and heavy metal contents, and bioactive compounds. The dried raw aquatic weeds and paper sheets showed similar proximate compositions, with carbohydrates being the highest component (50.38–64.63%), followed by crude protein (15.25–19.13%), ash (9.30–15.88%), and lipid (1.55–3.43%). The raw weeds and paper sheets were rich in essential minerals like Na, Ca, and Zn with contents ranging from 27.7 mg/100 g to 30.4 mg/100 g, 126.8 mg/100 g to 489.65 mg/100 g, and 4.5 mg/100 g to 16.3 mg/100 g, respectively. Acceptable levels of heavy metals, including Ni, Pb, and Cu, were found. The paper sheets contained seven essential and eight non-essential amino acids. Among the essential amino acids, the phenylalanine content was the highest at 2735.9 mg/100 g in E. fluctuans paper sheets, followed by methionine at 2377.29 mg/100 g in the raw E. fluctuans and histidine at 1972.6 mg/100 g in E. fluctuans paper sheets. A. philoxeroides sheets showed the highest total amino acid content (16,146.81 mg/100 g), while I. aquatica showed the lowest (13,118.67 mg/100 g). The aquatic weed paper sheets were rich in bioactive compounds, and the numbers in E. fluctuans, A. philoxeroides, and I. aquatica paper sheets were 31, 33, and 40, respectively. There were no significant changes in the nutritional content of the aquatic weeds in paper sheet form compared with the raw weeds, which suggests promising prospects for their production and consumption as a source of nutrition and bioactive compounds.

1. Introduction

Bangladesh possesses an enormous area of wetland that supports naturally occurring aquatic and semi-aquatic plants, providing a cost-effective source of food for fish, wildlife, and people [1]. These aquatic weeds are a renewable biomass and hold immense medicinal value. They contain a variety of nutritional compounds, including protein, amino acids, lipids, polysaccharides, minerals, vitamins, polyphenols, and other bioactive compounds. Leafy vegetables, such as aquatic weeds, are known to be low in fat and calories while providing various vitamins, minerals, and fiber [2]. Dried seaweed paper, particularly nori, made from the seaweed species Porphyra sp., is popular in many Asian countries, including Japan, Korea, and China. Nori is highly valued by local and international markets due to its high nutrition level, unique texture, compactness, and pleasant taste. It is also possible to produce artificial nori using other seaweeds or non-seaweed materials [3]. The production of edible paper sheets from aquatic weeds could be a feasible approach to attracting consumers and promoting the consumption of aquatic weeds throughout the country and across all classes of the population. Further research can focus on investigating the nutritional properties of aquatic weeds and the paper sheets, as well as exploring production methods for edible paper sheets. The present research opens up exciting possibilities for an innovative culinary and nutritional application of locally available aquatic weeds. Updated research and information in this area can help pave the way for responsible and wide applications of new food processing techniques for the wider population. In Bangladesh, among the different available aquatic weeds, helencha (Enhydra fluctuans), malancha (Alternanthera philoxeroides), and kalmi (Ipomea aquatica) are consumed as important vegetables.

A. philoxeroides, commonly known as alligator weed or Malanchashak in Bangladesh, is not only used as a food but also as a medicine. It is consumed as leafy vegetables and has traditional uses in treating various conditions such as hazy vision, night blindness, malaria, postnatal complaints, diarrhea, dysentery, and puerperal fever [4]. A. philoxeroides is also rich in iron and can be used in salads [5]. E. fluctuans is an aquatic plant naturally found in marshy areas in tropical regions and countries like India, Bangladesh, Malaysia, China, Southeast Asia, and tropical Africa [6]. Traditionally, the leaves and stems of E. fluctuans have been used to treat various diseases including gastric ulcers, diabetes, skin diseases, smallpox, kidney stones, and inflammation [7]. The leaves also possess antimicrobial properties [8,9]. Phytochemical analysis of E. fluctuans has shown the presence of flavonoids, triterpenes, carbohydrates, reducing sugars, saponins, phenols, diterpenes, proteins, and tannins [10]. I. aquatica is a common and highly nutritious plant that offers benefits to the body, skin, and brain. It naturally grows in tropical and subtropical countries and is widely cultivated in China, Indonesia, Thailand, Vietnam, Myanmar, the Philippines, Bangladesh, and India [11]. In Southeast Asia, I. aquatica is used to treat conditions like piles, nosebleeds, and high blood pressure. In Ayurveda, leaf extracts are used to treat jaundice and nervous disorders [12]. In Sri Lanka, water spinach is known for its insulin-like properties, and extracts of I. aquatica have shown blood-sugar-lowering effects [13]. Bioactive compounds and antimicrobial substances have also been detected in I. aquatica [14,15]. This plant exhibits anticancer, antioxidant, anti-inflammatory, diuretic, antitumor, chemo-preventive, and antimicrobial activities and is used in vaccine formulations [15].

The extent of micronutrient deficiency in many countries exceeds that of energy malnutrition. In a global perspective, 2.3 billion people were suffering from food insecurity and malnutrition in 2021 [16]. Aquatic weeds are a valuable source of proteins, fats, carbohydrates, vitamins, minerals, and fiber, which are essential for maintaining good health and preventing diseases such as cancer, coronary heart attacks, and diabetes. Despite the availability of numerous aquatic weeds in Bangladesh, the population of this country is not accustomed to consuming aquatic plants. Furthermore, there is a scarcity of reports that highlight the various biofunctional and nutritional properties of aquatic weeds. It is anticipated that approximately 135 M people of this country would benefit from the consumption of paper sheets made from aquatic weeds. Therefore, the preparation of edible paper sheets from the aquatic weeds found in Bangladesh can provide an easier way for people, including children, to consume them. The objectives of the present study were to assess the feasibility of preparing edible paper sheets from three available aquatic weeds in Bangladesh, namely, Helencha (E. fluctuans), Malancha (A. philoxeroides), and Kalmi (I. aquatica). The study also aimed to evaluate the nutritional composition (proximate composition, amino acids, minerals, heavy metals) and perform GC-MS analysis of both the raw aquatic weeds and the edible paper sheets made from them.

2. Materials and Methods

2.1. Collection of Samples and Preparation of Edible Paper Sheets

Helencha (Enhydra fluctunas), malancha (Alternanthera philoxeroides), and kalmi (Ipomoea aquatica) were collected from different locations of Jashore district in Bangladesh. The aquatic weeds were properly rinsed with clean water. Then, the weeds were ground using a blender (WBL-13EC25N, Walton, Dhaka, Bangladesh). A mixture of aquatic weeds and water was added to the blender in a ratio of 2:1 (aquatic weeds to water) and mashed to create a paste. Subsequently, the aquatic weed paste was boiled using a gas oven. The mashed paste was then poured into a non-sticky stainless-steel pan. While boiling, 0.5% testing salt and 1% corn flour were added according to the quantities listed in

Table 1. Ingredients and their quantity for the formulation of edible aquatic weed paper sheets.

Sample	Quantity (g)	Corn Flour (g)	Testing Salt (g)	Water (mL)
E. fluctuans	400	4	2	200
A. philoxeroides	400	4	2	200
I. aquatica	400	4	2	200

, to enhance the taste and make the paste sticky. The paste was boiled at approximately 100 °C for 10 min. The mixture was then poured into a rectangular-shaped sieve covered with cheesecloth. Afterward, it was left to sit for 10 min to allow the excess water to seep through and placed in a hot air oven for drying at 65 °C for 12 h. Once dried, the paper was carefully pulled away from the cheesecloth. The different aquatic weeds used in the present study and the developed paper sheets are presented in Figure 1. The raw aquatic weeds were also dried and ground to compare the variations in nutritional properties with the edible paper sheets.

2.2. Analysis of Proximate Composition

The proximate composition such as moisture, protein, lipid, and ash content was analyzed following the methods of AOAC (2005) [17]. The carbohydrate content of raw weeds and aquatic weed paper sheets was determined indirectly by subtracting the moisture, protein, and ash content from one hundred [18].

2.3. Determination of Amino Acid Composition

An amino acid analyzer (LA 8080, Hitachi, Tokyo, Japan) equipped with a high-performance cation-exchange column and operated at a column temperature of 57 °C was used to determine the amino acid content, following an existing method with some modifications [19]. For pretreatment, 1 g of the sample was added to 25 mL of 6 M HCl in a glass tube. The tube was then placed in a sand bath and heated to 110 °C for 24 h. The resulting solid was dried using an HCl evaporation process, mixed with 6 mL of distilled water, and filtered using a 0.45 μm syringe filter.

2.4. Determination of Mineral and Heavy Metals Contents

The minerals and heavy metals contents of the sample were determined by using ICP-OES optima 2000 DV (Perkin Elmer, Waltham, MA, USA) following the method of Islam et al. with minor alternations [19]. Initially, 1.0 g of each dried sample was placed in a muffle furnace at 600 °C for 6 h to facilitate ash formation. After the ash was formed, 4 mL of HNO₃ and 1 mL of H₂O₂ were added to the ash powder, and distilled water was added to create a 60 mL solution. The solution was heated on a hot plate and reduced to half of its original volume (30 mL). Subsequently, 4 mL of distilled water and 1 mL of H₂O₂ were added, and the solution (35 mL) was heated again to reduce it to half its original volume (17.5 mL). Distilled water was then added to bring the solution to a total volume of 50 mL, which was subsequently filtered through a 125 mm filter paper. Filtering was performed twice, and after that, the solution was ready to be tested for minerals and heavy metals analysis. The operational conditions of the instrument were maintained as in a previous report [20].

2.5. Gas Chromatography Mass Spectrometry (GC-MS) Analysis

The extract for GC-MS analysis was prepared as follows: 10.0 g of pulverized aquatic weed and paper sheet powders individually was added to a 100 mL glass beaker. Subsequently, 50 mL of ethanol was added to the sample, and the mixture was stirred using a magnetic stirrer for 5 h at a rotation speed of 400 rpm. To prevent solvent evaporation, the beaker was covered with aluminum foil. The sample was then filtered using double filter paper. Finally, the filtered sample was passed through a syringe filter (0.45 μm) and stored in a glass vial. For the analysis, the Clarus 690 gas chromatograph was employed. This instrument utilized a column (Elite-35, 30 m × 0.25 mm, 0.25 μm film thickness; PerkinElmer, Waltham, MA, USA) and the Clarus@ SQ 8C mass spectrometer (PerkinElmer, Waltham, MA, USA). Initially, a 1 μL sample solution was injected, and pure helium (99.99%) was used as the carrier gas with a flow rate of 1 mL/min for a runtime of 40 min. The analysis was performed in electron ionization (EI) mode at high energy (70 eV). The inlet temperature was maintained at a constant 280 °C, while the oven temperature was programmed to start at 60 °C for 0 min and then increase at a rate of 5 °C/min until reaching 240 °C. The compounds present in the sample were identified using the database of the National Institute of Standards and Technology (NIST).

2.6. Statistical Analyses of Experimental Data

Microsoft Excel was utilized to generate the graph and table for the study. All experiments were performed in triplicate, and the results are reported as the mean ± standard deviation (SD). Data analysis was conducted using IBM SPSS software version 20, and a significance level of 5% (p < 0.05) was employed. The difference between the means was obtained via Duncan’s multiple range test.

3. Results and Discussion

3.1. Proximate Composition Analysis

The proximate compositions of the studied edible paper sheets and raw aquatic weeds are presented in Figure 2.

3.1.1. Moisture Content of Edible Aquatic Weed Paper Sheets

In this study, the moisture content of different paper sheets was evaluated, and it was found that E. fluctuans exhibited the highest moisture content (10.62%), while I. aquatica showed the lowest moisture content (8.61%). Therefore, the sequence of moisture content among the paper sheets was as follows: E. fluctuans (10.62%) > A. philoxeroides (9.36%) > I. aquatica (8.61%). When considering the raw samples, the sequence of moisture content was I. aquatica (11.06%) > E. fluctuans (10.51%) > A. philoxeroides (9.82%). Thus, it can be observed that the moisture content was higher in the raw samples compared with the processed paper sheets due to the drying of the paper sheets for an elongated period of time and the textural changes in the weeds. A previous study reported moisture content values of 10.30% for I. aquatica and 10.06% for E. fluctuans [21]. The moisture content of E. fluctuans varied from 9.9% to 13.4% depending on seasonal variations [22]. According to Pulipati et al., the moisture content of A. philoxeroides was 10% [23]. These findings align closely with the results obtained in the present study, suggesting a similar maximum moisture content across the different plant species. The proximate composition of aquatic weeds is influenced by various factors, including environmental conditions, processing techniques, soil chemistry, and so on. These factors help align the moisture content of the studied aquatic weeds with that of previously reported weeds.

3.1.2. Ash Content of Edible Aquatic Weed Paper Sheets

The ash content in foods determines the minerals consists of inorganic minerals such as calcium, potassium, phosphorus, sodium, magnesium, and trace elements [24]. The ash content of the paper sheets made from aquatic weeds was found with the following sequence: A. philoxeroides (10.58%) > E. fluctuans (10.16%) > I. aquatica (9.3%). In terms of the raw aquatic weeds, the sequence of ash content was A. philoxeroides (15.88%) > E. fluctuans (13.28%) > I. aquatica (11.98%). These results indicate a decrease in ash content in the paper sheets compared with the raw samples due to the heat processing. Among the different plant species, A. philoxeroides exhibited the highest ash content, while I. aquatica demonstrated the lowest, both in the raw and paper forms. In a study conducted on the proximate composition of commonly found edible aquatic plants in Bangladesh, including E. fluctuans and A. philoxeroides, the ash content was determined to be 17.28% in the stem and 16.13% in the leaf for E. fluctuans and 14.73% in the stem and 13.93% in the leaf for A. philoxeroides [22]. Another study focused on the biochemical analysis of I. aquatica, revealing an ash content of 13% [21]. Research on the nutritional composition of water spinach (I. aquatica) found an ash content of 10.83 ± 0.83% [25]. Datta et al. (2019) reported an ash content of 16.37% for E. fluctuans and 15.15% for I. aquatic [26]. These findings show both similarities and differences when compared with the present study. Overall, the present study demonstrates close similarities and some variations in ash content compared with other relevant studies in the field. Differences in environmental conditions, such as variations in soil composition, harvesting methods, ingredient varieties, and temperature, have also been considered as contributing factors to the disparities in nutritive value among different aquatic weeds.

3.1.3. Crude Protein Content of Edible Aquatic Weed Paper Sheets

The study revealed the respective crude protein contents of the three raw aquatic weeds: A. philoxeroides (21.66%), E. fluctuans (19.13%), and I. aquatica (18.12%). Similarly, in the paper sheets, the protein contents were observed in the following order: A. philoxeroides (17.12%), E. fluctuans (16.23%), and I. aquatica (15.25%). The protein content in the paper sheets decreased compared with the raw aquatic weeds due to the cooking and heat processing involved. The protein content of two aquatic weeds in Bangladesh was as follows: E. fluctuans showed the values of 19.64% for the stem and 20.58% for the leaf, and A. philoxeroides exhibited 19.97% for the leaf and 16.5% for the stem [22]. The protein content in A. philoxeroides of Bangladeshi origin was found to be 26.96% [27]. A study on the biochemical analyses of I. aquatica revealed that young shoots contained 16.8% protein [21]. Furthermore, the nutritional quality and safety aspects of wild vegetables consumed in Bangladesh showed crude protein contents of 16.69% in Helencha (E. fluctuans) and 21.45% in Kalmishak (I. aquatica) [28]. Protein is a vital nutrient that plays numerous essential roles in the human body, including tissue growth and repair, enzyme and hormone production, immune function, and transport and storage in the animal body [29,30,31].

3.1.4. Lipid Content of Edible Aquatic Weed Paper Sheets

The results of the present study indicated the lipid content of raw aquatic weeds as follows: E. fluctuans (2.98%), A. philoxeroides (2.72%), and I. aquatica (3.43%). Similarly, the lipid content in the edible paper sheets was observed in the following order: E. fluctuans (1.95%), A. philoxeroides (1.59%), and I. aquatica (2.11%). Among the raw samples, I. aquatica exhibited the highest lipid content (3.43%), while A. philoxeroides had the lowest (2.72%). In contrast, among the paper sheet samples, A. philoxeroides showed the lowest lipid content (1.59%), while I. aquatica showed a slightly higher content (2.11%). Therefore, this study suggests that there is a slight difference in lipid contents between raw aquatic weeds and paper samples. It is worth noting that aquatic weeds generally contain a low amount of lipids. An investigation of four edible aquatic weeds in Bangladesh reported lipid contents in E. fluctuans and A. philoxeroides leaves ranging from 1.12% to 2.96%, and in stems ranging from 1.11% to 2.02% [22]. Satter et al. (2016) analyzed various wild vegetables, including Dhekishak, Helencha, Kalmishak, Patshak, and Shapla stems, which contained crude fat contents of 2.27%, 2.66%, 3.34%, 4.76%, and 1.45%, respectively [28]. The lipid content in I. aquatica and E. fluctuans were reported to be 2.19% and 1.10%, respectively [32]. These findings align closely with the combination of results from previous studies and the present study. Lipids of aquatic weeds are important due to various health benefits such as providing essential fatty acids which are known for their positive effects on cardiovascular health, brain function, inflammation regulation, etc. [22,32].

3.1.5. Carbohydrate Content of Edible Aquatic Weed Paper Sheets

The present study revealed the carbohydrate content of edible paper sheets, with the highest content found in the I. aquatica paper (64.63%), followed by the A. philoxeroides paper (60.89%), and the lowest content was found in the E. fluctuans paper (60.04%). In comparison, the carbohydrate content in raw aquatic weeds followed the following sequence: I. aquatica raw (55.41%) > E. fluctuans raw (54.09%) > A. philoxeroides raw (50.38%). These findings indicate that the carbohydrate content in paper samples was higher than in raw samples, possibly due to the cooking and heat processing involved. In a study conducted on wild edible plants, the carbohydrate content in Dhekishak, Helencha, Kalmishak, Patshak, and Shapla stems was reported to be 57.69%, 61.61%, 52.78%, 60.21%, and 76.34%, respectively [28]. Umar et al. (2007) analyzed the nutritional composition of water spinach leaves and found a carbohydrate content of 54.20 ± 0.68% [24]. Igwenyi et al. (2011) determined the proximate composition of I. aquatica and reported a carbohydrate content of 42.18% [33]. Dutta et al. (2015) found the carbohydrate content of I. aquatica (10.51%) and E. fluctuans (9.64%) on a weight sample basis [32]. The biochemical composition of Alternanthera sessilis was reported to have a carbohydrate content of 74.56% [34]. These previous studies demonstrated both similarities and variations in carbohydrate content with the findings of the present study. Variations in environmental factors, including differences in soil composition, harvesting methods, ingredient varieties, and temperature, have been recognized as potential contributors to variations in the nutritional value among different aquatic weeds.

3.2. Minerals and Heavy Metal Content of Edible Aquatic Weed Paper Sheets

In this study, the mineral content of various aquatic weed samples was analyzed. Among the paper samples, the A. philoxeroides paper had a significantly higher calcium (Ca) content (489.65 ± 5.55 mg/100 g) compared with E. fluctuans (433.3 ± 4.94 mg/100 g) and I. aquatica (126.8 ± 2.17 mg/100 g). Similarly, among the raw aquatic weeds, A. philoxeroides showed a higher Ca content (442.85 ± 4.53 mg/100 g) compared with E. fluctuans (397.1 ± 2.49 mg/100 g) and I. aquatica (281.9 ± 4.09 mg/100 g) (

Table 2. Mineral and heavy metal contents (mg/100 g) of raw aquatic weeds and edible aquatic paper sheets.

Minerals and Heavy Metals	Enhydra fluctuans (Raw)	Alternanthera philoxeroides (Raw)	Ipomoea aquatica (Raw)	Enhydra fluctuans (Paper)	Alternanthera philoxeroides (Paper)	Ipomoea aquatica (Paper)
Na	29.1 ± 0.52 b	27.7 ± 0.38 c	28.9 ± 0.55 b	30.4 ± 0.36 a	29.3 ± 0.36 ab	29.2 ± 0.24 b
Ca	397.1 ± 2.49 c	442.85 ± 4.53 b	281.9 ± 4.09 d	433.3 ± 4.94 b	489.65 ± 5.55 a	126.8 ± 2.17 e
Zn	6.01 ± 0.27 b	16.29 ± 0.81 a	6.11 ± 0.32 b	5.92 ± 1.21 c	15.55 ± 0.92 a	4.55 ± 1.13 d
Ni	1.24 ± 0.12 b	1.15 ± 0.37 b	1.39 ± 0.26 a	0.34 ± 0.08 d	1.22 ± 0.32 b	0.77 ± 0.17 c
Cu	2.35 ± 0.25 c	4.39 ± 0.33 a	3.74 ± 0.16 ab	3.57 ± 0.3 b	4.13 ± 0.17 a	2.16 ± 0.39 c
Pb	Nd	Nd	0.14 ± 0.03 a	0.04 ± 0.002 b	Nd	0.18 ± 0.05 a
As	Nd	Nd	0.02 ± 0.001 a	Nd	Nd	0.03 ± 0.001 a
Cr	0.53 ± 0.06 b	0.45 ± 0.03 c	0.78 ± 0.03 a	0.57 ± 0.02 b	0.58 ± 0.04 b	0.69 ± 0.05 a

Values are presented as means ±standard deviation of triplicates. Values with the same letter in each row are not significantly different (p < 0.05). Nd = Not detected.

). Regarding sodium (Na) content, in the paper samples, E. fluctuans had a significantly higher level of Na (30.4 ± 0.36 mg/100 g) compared with A. philoxeroides (29.3 ± 0.36 mg/100 g) and I. aquatica (29.2 ± 0.24 mg/100 g). In the raw aquatic weed samples, E. fluctuans (29.1 ± 0.52 mg/100 g) had a significantly higher level of Na compared with A. philoxeroides (27.7 ± 0.38 mg/100 g) and I. aquatica (28.9 ± 0.55 mg/100 g). When examining the zinc (Zn) content, among the edible paper sheets, the A. philoxeroides paper (12.55 ± 0.92 mg/100 g) had significantly higher Zn contents compared with the I. aquatica paper (4.55 ± 0.13 mg/100 g) and E. fluctuans paper (5.92 ± 0.21 mg/100 g). Among the raw aquatic weeds, A. philoxeroides (16.29 ± 0.81 mg/100 g) had the highest Zn content compared with E. fluctuans (6.01 ± 0.27 mg/100 g) and I. aquatica (6.11 ± 0.32 mg/100 g). Thus, this study demonstrated that the paper samples contained higher levels of minerals (Ca, Na, and Zn) compared with the raw samples (

Table 3. Amino acid composition and contents (mg/100 g) of raw aquatic weeds and edible aquatic paper sheets.

Amino Acid	Enhydra fluctuans (Raw)	Alternanthera philoxeroides (Raw)	Ipomoea aquatica (Raw)	Enhydra fluctuans (Paper)	Alternanthera philoxeroides (Paper)	Ipomoea aquatica (Paper)
Essential Amino Acid
Thr	Nd	Nd	24.99 ± 0.67 a	Nd	Nd	24.99 ± 0.75 a
Val	77.22 ± 1.56 a	Nd	Nd	77.22 ± 1.23 a	Nd	27.49 ± 0.71 b
Met	2377.29 ± 13.31 b	2265.31 ± 7.45 c	Nd	1741.06 ± 6.5 d	2616.44 ± 9.62 a	Nd
Phe	2139.22 ± 8.74 b	948.75 ± 6.28 d	1914.1 ± 5.87 c	2735.9 ± 14.67 a	925.65 ± 7.21 d	2187.9 ± 13.45 b
Lys	Nd	512.12 ± 4.61 c	217.54 ± 2.87 d	557.72 ± 3.98 b	807.38 ± 3.87 a	Nd
His	1160.95 ± 8.67 c	753.56 ± 6.7 d	1243.87 ± 13.48 b	1972.67 ± 11.7 a	748.57 ± 4.5 d	1177.22 ± 8.9 c
Leu	7.2 ± 0.12 d	886.76 ± 4.52 c	1388.6 ± 7.43 a	Nd	1066.99 ± 5.23 b	Nd
Non-Essential Amino Acid
Asp	Nd	Nd	Nd	439.93 ± 3.34 b	Nd	27.95 ± 4.83 a
Ser	226.28 ± 1.35 a	Nd	Nd	221.55 ± 1.56 a	Nd	198.45 ± 0.94 b
Glu	175.2 ± 1.43 c	645.45 ± 2.21 b	Nd	73 ± 1.08 d	1964.97 ± 10.29 a	148.89 ± 1.32 c
Gly	1275 ± 6.69 d	1234.74 ± 5.84 d	6012.12 ± 15.65 a	2778.75 ± 7.45 c	821.25 ± 5.53 e	5609.25 ± 18.75 b
Ala	Nd	8721.25 ± 14.76 a	Nd	Nd	7195.54 ± 16.28 b	Nd
Cys	Nd	Nd	2327.43 ± 7.59	Nd	Nd	Nd
Tyr	500.46 ± 4.5 b	Nd	Nd	3420.82 ± 12.6 a	Nd	427.16 ± 4.34 c
Pro	2025.98 ± 9.68	Nd	Nd	Nd	Nd	Nd
Arg	4539.6 ± 15.37 a	Nd	Nd	Nd	Nd	4250.82 ± 12.43 b
Total	14,558.42	15,967.94	13,128.67	14,018.64	16,146.81	14,079.43

Values are presented as means ±standard deviation of triplicates. Different superscript letters on each row indicates significant differences (p < 0.05). Nd = not detected.

).

Furthermore, in the heavy metal test, copper (Cu), nickel (Ni), lead (Pb), and arsenic (As) were detected. Among the samples, the raw I. aquatica had the highest Ni content (1.39 ± 0.26 mg/100 g) compared with the raw A. philoxeroides (1.15 ± 0.37 mg/100 g) and raw E. fluctuans (1.24 ± 0.12 mg/100 g). Among the paper sheets, the A. philoxeroides paper (1.22 ± 0.32 mg/100 g) had the highest Ni content compared with the E. fluctuans paper (0.34 ± 0.08 mg/100 g) and I. aquatica paper (0.77 ± 0.17 mg/100 g). However, the raw weed samples contained higher Ni levels than the paper sheets. Regarding other metals, raw A. philoxeroides had the highest Cu content (4.39 ± 0.33 mg/kg), while the lowest was found in the I. aquatica paper (2.16 ± 0.39 mg/100 g). Lead (Pb) was detected in the E. fluctuans paper (0.04 ± 0.002 mg/100 g) and raw I. aquatica (0.14 ± 0.03 mg/100 g). All of the tested heavy metals, including Ni, Cu, Pb, and As, were found to be within the acceptable limits for consumption. Surface water pollution resulting from human activities and anthropogenic causes plays a significant role in heavy metal contamination in aquatic ecosystems, which also affects the aquatic weeds. The presence of trace metal contaminants is of great concern due to their potential for environmental and human toxicity. Chromium and its compounds represent toxic metals that find their way into natural water systems through various industrial waste streams. The primary sources of these pollutants include leather tanning, textile dyeing, electroplating, and metal finishing industries, leading to substantial environmental and public health issues.

In a previous study, the mineral compositions of A. sessilis red (ASR) and A. sessilis green (ASG) were examined. ASR was found to contain 236.36 ± 4.47 mg/100 g of calcium, 7.02 ± 0.01 mg/100 g of potassium, 68.14 ± 8.00 mg/100 g of sodium, and 6.67 ± 0.35 mg/100 g of zinc. On the other hand, ASG had 7.02 ± 0.01 mg/100 g of calcium, 199.02 ± 0.18 mg/100 g of potassium, 0.67 ± 0.07 mg/100 g of sodium, and 0.50 ± 0.00 mg/100 g of zinc. The copper content was 1.13 ± 0.12 mg/100 g in ASR and 0.85 ± 0.01 mg/100 g in ASG [35]. The mineral composition of A. sessilis is influenced by soil fertility, as minerals are absorbed from the soil, as well as genetic factors and fertilizer usage [36]. The mineral content per 100 g of A. sessilis included 285.78 ± 5.95 mg of sodium, 510.35 ± 9.69 mg of calcium, phosphorus, magnesium, manganese, and copper at 1.6 ± 0.02 mg, and zinc at 8.9 ± 2.25 mg [33]. The plant was particularly rich in iron and manganese. Ndamitso et al. (2015) studied wild I. aquatica and found that the leaves of I. aquatica exhibited higher levels of magnesium (2300 ± 0.023 mg/kg), phosphorus (225 ± 0.003 mg/kg), iron (155 ± 0.020 mg/kg), zinc (25 ± 0.000 mg/kg), manganese (8 ± 0.002 mg/kg), and copper (36 ± 0.002 mg/kg) compared with the stems [37]. On the other hand, the stems had higher levels of sodium (1000 ± 0.020 mg/kg), potassium (5562.5 ± 0.003 mg/kg), and calcium (65.00 ± 0.01 mg/100 g). These minerals play important roles in various biological processes. Calcium, phosphorus, and magnesium are involved in bone growth and turnover, while iron is essential for the formation of hemoglobin [26]. These findings suggest that regular consumption of aquatic weed paper sheets can help combat malnutrition and other health disorders due to its abundance of macro- and microelements.

3.3. Amino Acid Composition in Aquatic Weed Paper Sheets

The amino acids found in the three raw aquatic weeds and edible aquatic weed paper sheets are presented in Table 3 and Figure 3. Both essential and non-essential amino acids were detected including phenylalanine, histidine, glycine, and glutamic acid. Among the essential amino acids, the phenylalanine content was the highest at 2735.9 mg/100 g in the E. fluctuans paper sheets, followed by methionine at 2377.29 mg/100 g in the raw E. fluctuans and histidine at 1972.6 mg/100 g in the E. fluctuans paper sheets. Of the non-essential amino acids, the alanine content was the highest at 8721.23 mg/100 in the raw A. philoxeroides, followed by glycine at 6012.12 mg/100 in the raw I. aquatica and arginine at 4539.60 mg/100 g in the raw E. fluctuans weeds. Among all the paper sheets, the A. philoxeroides paper contained the highest amount of amino acids (16,146.81 mg/100 g). Similarly, among all the raw aquatic weeds, raw A. philoxeroides showed the highest amount of amino acids (15,967.94 mg/100 g). The E. fluctuans paper and I. aquatica paper showed total amounts of amino acids of 14,018.64 mg/100 g and 14,079.43 mg/100 g, respectively. On the other hand, the raw I. aquatica had the lowest amount of total amino acids (13,118.67 mg/100 g). The predominant amino acid in A. philoxeroides (both raw and paper) was alanine at 8721.25 ± 14.76 mg/100 g and 7195.54 ± 16.28 mg/100 g, respectively. In the raw I. aquatica and its paper sheets, the major amino acid was glycine at 6012.12 ± 15.65 mg/100 g and 5609.25 ± 18.75 mg/100 g, respectively. The highest amount of phenylalanine (2735.9 ± 14.6 mg/100 g) was found in the E. fluctuans paper sheets.

The study conducted on A. philoxeroides found that glutamic acid (20.86%), serine (8.28%), aspartic acid (7.82%), and arginine (6.52%) were abundant in the plant [38]. Essential amino acids such as leucine (4.3%), isoleucine (4.24%), and lysine (3.88%) were also present in substantial amounts. The plant contained approximately 24% of total nitrogen, indicating its potential as a good dietary source. There were 18 amino acids identified in varying proportions in I. aquatic [37]. Glutamic acid was found to be the amino acid with the highest content in both the leaves (11.91 ± 0.015 g/100 g protein) and stems (7.27 ± 0.020 g/100 g protein). Among the essential amino acids, leucine had the highest concentration in both the leaves (7.54 ± 0.30 g/100 g protein) and stems (6.39 ± 0.583 g/100 g protein). Cystine and tryptophan were identified as the least abundant essential amino acids in the leaves (0.71 ± 0.002 g/100 g protein) and stems (0.53 ± 0.153 g/100 g protein), respectively. According to A. philoxeroides contained various amino acids, including lysine, histidine, arginine, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, and phenylalanine [39].

3.4. Major Bioactive Compounds in Aquatic Paper Sheets Determined via GC-MS

Among the three raw aquatic weeds, 29 compounds were identified in EfR (E. fluctuans raw), 36 compounds were identified in ApR (A. philoxeroides raw), and 37 compounds were identified in IaR (I. aquatica raw). Among the three edible paper sheets, 31 compounds were identified in EfP (E. fluctuans paper), 33 compounds were identified in ApP (A. philoxeroides paper), and 40 compounds were identified in IaP (I. aquatica paper). The highest number of compounds was identified in IaP, and the lowest number of compounds was identified in EfR. The retention time (RT), name of the compounds, peak area (%), molecular weights, and their molecular formulas are shown in

Table 4. Compounds identified through GC-MS analysis of the raw aquatic weeds and edible aquatic weed paper sheets.

SL. No	Retention Time	Identified Compounds	Molecular wt.	Molecular Formula	Peak Area (%)
					EfR	ApR	IaR	EfP	ApP	IaP
1	3.053	N-Methyl-3,4-Methylenedioxyamphetamine	193	C11H15NO2	-	-	0.05	-	-	-
2	3.174	N-Methyl-3,4-Methylenedioxyamphetamine	194	C11H15NO2	-	-	-	-	-	0.03
3	3.697	Cyclohexyl Propionate	156	C9H16CO2	-	0.03	-	-	-	0.03
4	3.698	Cyclohexylmethylsilane	128	C7H16Si						0.08
5	3.712	2-Ethylbutyl Propionate	158	C9H18O2						0.1
6	3.818	Butanoic Acid, 2-Methyl	102	C7H12O3	-	-	-	-	-	0.1
7	4.287	Cyclobutanespiro-2′-Bicyclo[1.1.0]Butane-4′-Spirocyclobutane	134	C10H14	-	-	-	-	-	0.68
8	4.269	3-Cyclohexene-1-Acetaldehyde, Apha, 4-Dimethyl	152	C15H24O3						0.22
9	4.247	Benzene,1,3-Dimethyl	106	C8H10	-	-	0.70	0.30	0.91	-
8	4.289	Pyrimidine, 4-Methyl-	94	C5H6N2	-	-	0.49	-	-	-
10	5.69	Acrylic Acid, (5-Cyclopropylidenepentyl) Ester	180	C11H16O2	-	-	-	0.24	-	-
11	5.801	Cyclohexane, 1-Methylene-4-(1-Methylethenyl)-	136	C10H16	-	0.07	-	0.21	-
12	5.822	Benzenesulfonamide, N-(4-Hydroxyphenyl)-	249	C12H11NO3S	-	-	0.38	-	-	-
13	5.83	Trifluoroacetic Acid, 4-Methylcyclohex-3-Enylmethyl Ester.	222	C10H13F3O2	-	-	-	-	-	1.74
14	5.843	1,2-Cyclooctadiene	108	C8H12	-	-	-	0.91	0.58	0.75
15	6.217	1-Hexene, 3-Methyl-6-Phenyl-4-(1-Phenylethoxy)-	294	C21H26O	-	-	0.22	0.15	-	-
16	6.277	1-Hexene, 6-Phenyl-4-(1-Phenylethoxy)	280	C20H24O	-	-	-	0.07	-	-
17	6.773	Benzaldehyde,3-Chloro-5-Methoxy –	290	C16H15ClO3	-	-	-	0.29	-	-
18	6.907	Limonene	136	C10H16	-	-	0.78		1.40	1.31
19	7.69	Azacyclohexan-3-One, 1-Tert-Butyl-	155	C9H17O	-	-	-	0.52	1.41	-
20	7.712	3-Ethyl-2-Pentadecanone	254	C17H34O	-	-	1.3	-	-	-
21	7.715	Clofexamide	284	C14H21ClN2O2	-	0.30	3.25	-	1.41	-
22	7.72	3-Ethyl-2-Pentadecanone	254	C17H34O	-	-	0.68	-	1.41	2.40
23	7.81	Carbonic Acid, Decyl Phenyl Ester	278	C17H26O3	-	-	-	-	5.20	-
24	7.813	Carbonic Acid	320	C20H32O3	-	-	-	-	4.19	-
25	9.214	2-Propanoic Acid, Ethyl Ester	100	C5H8O2	-	-	-	-	-	3.83
26	9.425	1H-Imidazol-2-Amine	83	C3H5N3	-	1.59	-	-	-	-
27	9.432	(E)-4-Oxohex-2-Enal	112	C6H8O2	-	1.05	-	1.70	-	-
28	9.851	2-Ethylthiolane, S,S-Dioxide	148	C6H12O2S	-	-		-	-	2.42
29	9.725	D-Methionine	149	C5H11NO2S	-	-	-	-	3.22	-
30	9.85	Benzeneacetaldehyde	120	C8H8O	1.7	1.19	5.4	0.88	3.40	4.2
31	9.856	Cyclohexene, (1-Methylpropyl)-	140	C10H20	-	-	-	-	-	3.24
32	10.476	Sulfurous Acid, Di(Cyclohexylmethyl) Ester	274	C14H26O3S	-	-	-	-	1.25	-
33	10.482	Cycloheptanemethanol	128	C8H16O	-	-	-	-	2.78	-
34	10.494	Z-24-Tritriaconten-2-One	474	C33H64O	0.15	-	-	-	-	-
35	12.063	2-Cyclohexen-1-Ol, 4-Amino-5,6-Dimethoxy-	173	C8H15NO3	-	-	0.57	-	-	-
36	12.117	1-Propanamine, N,N-Dimethyl-3-[[1-(Phenylmethyl)-1h-Indazol-3-Yl]Oxy]-	309	C19H23N3O	-	-	-	-	-	0.52
37	12.123	1,3-Propanediamine, N,N,N′,N′-Tetramethyl	130	C25H54N2O2	-	-	-	-	-	1.72
38	12.404	Succinic Acid, 2-Chloro-5-Methylphenyl Tetradecyl Ester	438	C25H39ClO4	1.34	-	-	0.86	-	-
39	12.431	Acrylic Acid, Butyldimethylsilylmethyl Ester	200	C10H20O2Si	-	0.9	-	-	-	-
40	12.432	L-Proline, 2Tms Derivative	259	C11H25NO2Si2	-	-	1.45	-	-	-
41	12.857	Succinic Acid, 2-Chloro-5-Methylphenyl Tridecyl Ester	424	C24H37ClO4	0.86	-	-	-	-	-
42	12.43	Cyclopentanol, Tms Derivative	158	C8H18OSi	-	0.47	-	-	-	-
43	12.443	2-Butenoic Acid, 3-Methoxy-4-Nitro-, Methyl Ester	174	C6H9NO5	-	0.47	-	-	-	0.42
44	12.445	Dimethylisopropylsilyloxycyclobutane	172	C9H20OSi	-	-	1.45	-	-	-
45	13.04	Orcinyl Di-Tiglate	288	C17H20O4	-	0.90	-	-	-	-
46	13.109	Glycine	171	C2H5NO2	-	0.95	-	-	-	-
47	13.091	(E)-4-Oxohex-2-Enal	112	C6H8O2	-	-	-	-	4.43	-
48	13.124	Phenyl Angelate, 2-Allyl	216	C9H16O2	-	-	-	-	0.91	-
49	14.382	Benzaldehyde, 4-Methyl-	120	C13H14N4S	1.93	-	-	-	-	-
50	14.388	2-Butenoic Acid	86	C4H6O2	-	0.23	-	-	-	-
51	14.398	Benzaldehyde, 3-Benzyloxy-2-Fluoro-	230	C15H13FO3	-	-	-	-	1.35	-
52	14.436	Methyl 4-O-Benzyl-.Alpha.-L-Rhamnopyranoside	268	C14H20O5	-	-	-	-	-	1.50
53	14.564	2-Dimethyl(Octyl)Silyloxybutane	244	C14H32OSi	-	-	3.46	-	-	-
54	14.817	Phenylalanine	165	C9H11NO2	-	-	-	-	-	1.75
55	15.027	1,3-Bis(Trimethylsilyloxy)Pentane	248	C11H22O2Si2	-	-	1.39	-	-	-
56	15.072	2-Methyl-3-Ethyl-3-Hydroxyglutaric Acid	406	C17H38O8Si3	-	-	0.72	-	-	0.36
57	15.983	Cis-2,4-Dimethylthiane, S,S-Dioxide	162	C7H14O2S	-	-	-	-	-	1.73
58	15.984	Cyclobutanone, 2-(1,1-Dimethylethyl)-	126	C8H14O	-	-		-	-	1.04
59	16.289	2-Hydroxy-5-Methylbenzohydrazide	166	C8H10N2O2	-	-	-	-	0.62	-
60	16.441	Propanoic Acid, Propyl Ester	116	C6H12O2	-	-	7.02	-	-	-
61	16.627	Silane, Dimethoxydimethyl	120	C4H12OSi	-	-	3.45	-	-	1.04
62	16.93	Ethanone, 2-Ethoxy-1,2-Diphenyl	240	C16H16O2	-	0.46	-	-	-	-
63	16.931	4-Acetoxy-3-Methoxystyrene	192	C11H12O3		0.54
64	16.933	4-Hydroxy-2-Methylacetophenone	150	C9H10O2	-	-	-	-	2.23	-
65	17.284	4-Quinolinol	145	C9H7NO	-	-	-	-	-	1.87
66	17.628	Indole	117	C8H7N	-	0.54	-	-	-	-
67	17.697	7-Methyl-4-(1-Pyrrolidinyl)Pyrido[3,2-C]Pyridazine	214	C12H14N4	-	0.74	-	-	1.24	-
68	18.204	Phenol, 2,6-Dimethoxy-, Acetate	196	C10H12O4	0.19	-	-	-	-	-
69	18.70	Carveol	152	C10H16O	-	-	0.80	-	-	-
70	18.861	Phenanthrene, 3,6-Dimethoxy-9,10-Dimethyl-	266	C18H18O2	0.96	-	-	-	-	-
71	19.101	P-Mentha-1,8-Dien-7-Yl Acetate	194	C12H18O2	-	-	-	-	-	0.14
72	20.209	1-Methylene-2b-Hydroxymethyl-3,3-Dimethyl-4b-(3-Methylbut-2-Enyl)-Cy	222	C15H26O	0.13	-	-	0.38	-	-
73	20.532	Piperidine, 2-(Tetrahydro-2-Furanyl)-	155	C9H17NO	-	0.89	-	-	-	-
74	20.563	3-Carene	136	C10H16	-	-	-	0.55	-	-
75	20.606	Pipradrol	267	C18H21NO	1.26	0.88		-	1.46	-
76	20.956	1-Bromo-3,7-Dimethyl-2,6-Octadiene	217	C10H17Br	-	-	-	-	-	0.83
77	20.965	3,7,11-Trimethyl-3-Hydroxy-6,10-Dodecadien-1-Yl Acetate	282	C17H30O3	-	-	-	0.38	-	-
78	23.294	2(4h)-Benzofuranone, 5,6,7,7a-Tetrahydro-4,4,7a-Trimethyl-, (R)-	180	C11H16O2	-	-	-	-	1.67	-
79	24.104	Quinoline, 2-Ethyl-	157	C11H11N	0.11	0.19	0.41	-	0.27	-
80	24.851	Dl-Alanyl-Dl-Alanine	482	C17H28N2O5	-	0.16	-	-	-	-
81	26.446	1,5-Diphenyl-2H-1,2,4Trizoline-3-Thione-	253	C14H11N3S	-	-	-	0.35	-	-
82	26.869	Phthalic Acid, Di(3,4- Dimethylphenyl)Ester	374	C24H22O4	-	-	-	0.29	-	-
83	26.784	Carbonic Acid,2-Ethylhexyl Nonyl Ester	300	C18H36O3	-	-	0.56	-	-	-
84	26.791	Carbonic Acid, Bis(2-Ethylhexyl)Ester	286	C18H34O6	-	-	1.8	-	-	-
85	27.837	Imidazole, 2-Cyano-	230	C7H10N4O3S	-	-	0.44	-	-	-
86	27.84	Borazine,2,4-Dimethyl	109	C2H9B2O3	-	-	1.22	-	-	-
87	27.845	1-Amino-2-Methylpyridinium Iodine	236	C6H9IN2	-	-	0.67	-	-	-
88	27.96	Methyl 11-Methyl-Dodecanoate	228	C14H28O2	1.12	4.46	6.31	1.14	2.54	2.51
89	27.971	Tridecanoic Acid,12-Methyl-Methyl Ester	242	C15H30O2	0.42	0.86	-	0.89	-	-
90	27.988	Heptacosanoic Acid, 25-Methyl-,Methyl Ester	438	C29H58O2	3.14	0.23	-	0.78	1.5	-
91	27.318	Octadecanoic Acid, 11-Methyl-Methyl Ester	312	C20H40O2	-	-	-	-	-	1.21
92	27.997	Undecanoic Acid,10-Methyl-,Methyl Ester	214	C13H26O2	-	0.29	8.05	-	0.05	-
93	27.996	Methyl 8-Methyl-Nonanoate	186	C11H22O2	-	-	-	-	-	1.21
94	27.998	Tetradecanoic Acid, 10,13-Dimethyl-,Methyl Ester	270	C17H34O2	1.6	-	0.25	-	-	-
95	29.083	Dodecanoic Acid	200	C12H24O2	-	3.31	-	-	8.71	1.75
96	29.107	12-Bromododecanoic Acid	278	C12H23BrO2	7.93	-	1.25	7.93	-	-
97	29.102	N-Hexadecanoic Acid	256	C16H32O2	1.3	5.46	-	2.25	-	16.07
98	29.569	Triallylvinylsilane	178	C11H18Si	-	-	-	4.23	-	-
99	29.585	6-Hydroxy-4,4,7A-Trimethyl-5,6,7,7A-TetrahydrobenZofuran-2(4H)-One	196	C11H16O3	8.71	-	-	1.89	-	3.21
100	29.587	(R)-3-Methylene-6-(S)-1,2,2-Trimethylcyclopentyl	204	C15H24	-	-	-	-	8.60	-
101	29.588	1-Cyclopentene-1-Methanol, 2-Methyl-5-(1-Methylethyl)-	154	C10H18O	1.17	-	-	-	3.61	-
102	29.589	2-N-Butyladamantane	192	C14H24	-	-	-	-	-	1.81
103	29.591	5-Methoxy-Cyclooctene	140	C9H16O	-	-	-	1.56	-	-
104	30.304	Adenine	135	C5H5N5	-	-	4.48	-	-	-
105	31.44	PhytylTetradecanoate	506	C34H66O2	2.30	-	-	-	5.29	-
106	31.442	PhytylPalmitat	534	C35H38O2	8.60	-	-	-	-	-
107	31.446	Phytol	296	C20H40O	14.02	1.39	2.89	3.20	14.02	2.55
108	31.747	Chloroacetic Acid, Ddec-9-Ynyl Ester	258	C14H23ClO2	-	-	-	0.64	-	-
109	31.751	Methyl 10-Trans,12-Cis-Octadecadienoate	294	C19H34O2	3.19	2.54	2.33	-	-	-
110	31.755	3,10-Dioxatricyclo[4.3.1.0(2,4)]Dec-7-Ene	138	C8H10O2	-	-	-	2.80	-	-
111	31.756	Cyclohexene, 1-Pentyl-	152	C11H20	-	-	-	-	-	0.05
112	31.766	Cis,cis-2,8-Dimethylspiro[5.5]Undecane	180	C13H24	-	-	-	-	3.19	-
113	31.954	N-Propyl 9,12-Octadecadienoate	322	C21H38O2	-	1.41	-	-	-	-
114	32.16	11,14,17-Eicosatrienoic Acid, Methyl Ester	320	C21H36O2	1.59	12.33	1.91	-	3.81	1.66
115	32.163	1-Methyl-3-Ethyladamantane	178	C13H22	-	-	-	1.51	-	-
116	32.175	Methyl 8,11,14-Heptadecatrienoate	278	C18H32O2	-	-	-	-	5.29	-
117	32.182	9,12,15-Octadecatrienoic Acid, Methyl Ester	292	C24H40O4	-	7.19	11.66	-	-	-
118	32.483	Methyl 9,12-Heptadecadienoate	280	C18H32O2	-	1.84	-	-	-	-
119	32.810	2,4,7-Trioxabicyclo [4.4.0]Dec-9-Ene,8-Decyloxy-3-Phenyl	374	C23H34O4	5.29	-	-	-	-	-
120	32.859	1-Silacyclohexa-2,5-Diene	96	C5H8Si	-	4.61	-	-	-	-
121	32.876	Methyl 2-Hydroxy-Octadega Hydroxy-Octadeca-9,12,15-Trienoate	308	C19H32O3	-	-		-	-	4.11
122	32.893	1,4-Dimethyladamantane	164	C12H20		-	-	7.89	-	-
123	32.906	ThymylTiglate	232	C16H20O3	3.81	-	-	-	-	-
124	33.26	BicycloI [5.1.0]Octane, 8-Methylene-	122	C9H14	-	-	5.69	-	-	-
125	33.262	BUTYL 9,12,15-OCTADECATRIENOATE	334	C22H38O2	-	12.3	-	-	-	-
126	33.265	Methyl 10,13,16-Docosatrienoate	348	C23H40O2	-	-	-	-	-	13.42
127	35.962	Kauran-16-Ol	290	C20H34O	5.29	-	-	15.43	-	-
128	35.507	Androst-5-En-4-Onet	272	C19H28O	-	-	-	41.01	-	-
129	36.804	1-Cyclohexanone, 2-Methyl-2-(3-Methyl-2-Oxobutyl	196	C12H20O2	-	-	-	-	-	2.41
130	36.811	(1,5,5,8-Tetramethyl Bicyclo [4.2.1]NON-9-YL)-Acetic Acid	238	C15H26O2	-	-	-	-	-	4.89
131	36.988	Kauran-18-Al, 16-Hydroxy-, (4.Beta.)-	304	C20H32O2	2.45	-	-	-	4.83	7.54
132	37.545	Carbamimidothioic Acid,	313	C16H15N3O2S	9.57	-	-	-	-	-
133	37.299	Tamoxifin	371	C26H29NO	-	26.80	-	-	-	-
134	38.741	1,1′-Biphenyl, 6-[(2-Dimethylamino)Ethyl]-6′-[2-Phenylethyl]-	419	C27H36NO3	-	4.28	-	-	-	-
135	38.97	Succinic Acid, 1, 1, 1-Trifluroprop-2-YL(2-Chlorocyclohexyl) Methyle	344	C14H20ClF3O4	-	-	11.20	-	-	-
136	38.972	1-Oxacyclododec-6-Ene-2,10-Dione, 7-Methyl	210	C12H18O3	1.3	-	2.40	-	-	-

EfR = Enhydra fluctans Raw, ApR = Alternanthera philoxeroides Raw, IaR = Ipomoea aquatica Raw, EfP = Enhydra fluctans Paper, ApP = Alternanthera philoxeroides Paper, IaP = Ipomoea aquatica Paper.

. In EfP, the major compounds identified were Androst-5-En-4-One (41.01%), Kauran-16-Ol (15.43%), 12-Bromododecanoic Acid (7.93%), and 1,4-Dimethyladamantane (7.89%). In EfR, the major compound identified was 6-Hydroxy-4,4,7A-Trimethyl-5,6,7,7A-Tetrahydrobenzofuran-2(4H)-One (8.71%). In ApR, the major compounds identified were Tamoxifen (26.8%) and 11,14,17-Eicosatrienoic Acid, Methyl Ester (12.33%). In ApP, the major compounds identified were Dodecanoic Acid (8.71%) and Phytol (14.02%). In IaP, the major compound identified was n-Hexadecanoic Acid (16.07%). The samples shared common compounds, which included Benzeneacetaldehyde, Quinoline, 2-Ethyl-, Pipradrol, Methyl 11-Methyl-Dodecanoate, N-Hexadecanoic Acid, Phytol, and 11,14,17-Eicosatrienoic Acid, Methyl Ester.

Various compounds in A. philoxeroides were reported, including the highest concentration of the acetic acid 2-(2-methoxycarbonylamino-5-nitrophenylthio)-, methyl ester (31.9%), followed by 1,4-benzenediol, 2,5-bis(1,1-dimethylethyl)- (15.06%) [40]. These compounds were considered to be responsible for the observed biological activity in the study. Bhaigybati et al. (2020) conducted research on the GC-MS analysis of the methanolic extract of I. aquatica Forsk [15]. The analysis led to the identification of 40 compounds from the methanolic extract of the edible parts of I. aquatica Forsk. Among these compounds, 11 were identified as major compounds, including 1,5-Heptadiene-3,4-diol, 2,5-dimethyl, 9,12-Octadecadienoic acid, methyl ester (E,E), phytol, hexadecanoic acid, 5,8-Octadecadienoic acid, methyl ester, Ar-tumerone, 7-Tetradecyne, 2-Cyclohexen-1-ol, 3-bromo, 11,14-Eicosadienoic acid, methyl ester, and heptadecanoic acid, methyl ester. Pamila et al. (2017) conducted a GC-MS analysis of A. philoxeroides and A. bettzickiana [41]. The analysis showed different peaks, indicating the presence of various bioactive compounds with both low and high molecular weights. Five compounds were found to be commonly present in both plants: n-Hexadecanoic acid, 9,12-Octadecadienoic acid (Z,Z), Ar-tumerone, Bicycloheptane, 2,6,6-trimethyl, and Phenol, 5-(1,5-dimethyl-4-hexeny), Limonene. Muselli et al. (2000) investigated the dihydroperillaldehydes in the essential oil of E. fluctuans [42]. The chemical composition of E. fluctuans essential oil from Vietnam was analyzed using GC/retention indices and carbon-13 NMR spectroscopy. The major components identified were myrcene, limonene, and trans- and cis-dihydroperillaldehydes. This study reported the presence of these two isomers in nature for the first time.

4. Conclusions

Among the three edible paper sheets made from aquatic weeds, A. philoxeroides was the most nutritious, but the other two also contained substantial amounts of nutrition. Both the raw aquatic weeds and the edible paper sheets contained a significant amount of bioactive compounds. Although there were minor changes in nutrition due to the thermal process, there was a close similarity between the raw aquatic weeds and the edible paper sheets. The paper sheets prepared from the aquatic weeds also provided significant quantities of various macro- and microelements. These paper sheets could be a promising source of carbohydrates, proteins, lipids, polyphenols, and other bioactive compounds, making them suitable for individuals suffering from malnutrition. Furthermore, the minerals present in the samples can contribute to meeting dietary requirements. The bioactive compounds derived from aquatic edible plants possess antioxidant properties, helping to scavenge free radicals and prevent various diseases. Since the edible paper sheets retain a good amount of bioactive compounds, we can make the best use of these aquatic weeds in this form.