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Communication

Yellow Mealworm Composition after Convective and Freeze Drying—Preliminary Results

by
Michał Krzyżaniak
1,*,
Marek Aljewicz
2,
Anna Bordiean
1 and
Mariusz Jerzy Stolarski
1
1
Department of Genetics, Plant Breeding and Bioresource Engineering, Faculty of Agriculture and Forestry, University of Warmia and Mazury in Olsztyn, Plac Łódzki 3, 10-724 Olsztyn, Poland
2
Department of Dairy Science and Quality Management, Faculty of Food Sciences, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 7, 10-719 Olsztyn, Poland
*
Author to whom correspondence should be addressed.
Agriculture 2022, 12(2), 149; https://doi.org/10.3390/agriculture12020149
Submission received: 10 January 2022 / Revised: 15 January 2022 / Accepted: 17 January 2022 / Published: 21 January 2022
(This article belongs to the Section Agricultural Product Quality and Safety)
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Abstract

:
Insects are a potential source of food and feed for humans and livestock, and they can be consumed in different forms. A combination of freezing, blanching, and drying methods are often recommended to prolong the shelf life of insect-based foods and reduce their microbial loads. However, these processes affect the quality of the end product. Therefore, the aim of this study was to determine the extent to which various drying methods influence the selected physical and chemical parameters of yellow mealworm (Tenebrio molitor L.) larvae. Insects were blanched (for 60 and 120 s) and dried with the use of two methods: convective drying (at a temperature of 60 °C and 80 °C) and freeze-drying (−30 °C) for 12, 16 or 24 h. Blanched and dried insects were subjected to laboratory analyses. The examined samples were characterized by low moisture content in the range of 3.15% to 5.47%, and they differed considerably in water activity (0.06–0.55). Moisture content and water activity were substantially higher in larvae blanched for 60 s and freeze-dried than in larvae dried with the use of the remaining methods. However, no significant changes in the protein, fiber, or fat content of insects were found when drying parameters were modified. Therefore, nutritional composition and microbial loads in dried mealworm larvae should be investigated in the future.

1. Introduction

According to World Population Prospects, there were 7.7 billion people worldwide in 2019, and the global population is projected to reach 8.5 billion in 2030 and increase further to 9.7 billion by 2050. By 2050, the highest population growth is expected in Sub-Saharan Africa (52%) and Central and Southern Asia (25%) [1]. Urgent solutions are needed to feed the growing global population. Entomophagy, or the consumption of edible insects, is widely practiced around the world. Insects are consumed by nearly 2 billion people worldwide, mostly in tropical regions [2]. In Western cultures, insects often evoke fear or even disgust, which can be largely attributed to insufficient knowledge about edible insects and the absence of a food culture that embraces insects. However, effective communication and marketing strategies are gradually changing consumer attitudes towards entomophagy [3]. Insects are not only an alternative source of food for humans, but they can also be incorporated into the diets of livestock, including in aquaculture and in poultry and pig breeding [4,5,6,7]. There are predictions that fishmeal demand will increase by 4% annually until 2027. For South America soybean (half of the world production) production has increased by 160% in Brazil and by 57% in Argentina since 2000. In addition, Brazilian soybean production is projected to increase by 30% in 10 years [8,9]. Insect protein can be an alternative to these ingredients, especially as there are concerns about upper limits and sustainability of sourcing traditional raw material for feed production [10,11]. Yellow mealworm is the larval form of Tenebrio molitor L. (1758—Coleoptera: Tenebrionidae), one of the most widely produced and studied mealworm species in Europe. This insect species belongs to the Pterygota and is a typical representative of the beetles’ order (Coleoptera) and suborder of the multivorous beetles (Polyphaga). The head of the mealworm has the mouth and labrum to aid in its voracious eating habits. The thorax is built from three segments with a pair of short legs each, and the abdomen has nine segments. The yellow mealworm is a typical example of a darkling beetle (Tenebrionidae). Yellow mealworms contain 45.1–63.9% of protein and 18.2–35.1% of fat (including 70.0–77.7% of unsaturated fatty acids) on a dry matter basis [4,12,13,14]. Mealworms can be a source of vitamin D, vitamin E, B vitamins, choline, thiamin, and minerals (P, K, Mg, Zn, and Mn) [15,16,17].
Insects can be consumed in various forms, including live, marinated, cooked, fried, or as larval meal that is added to food and feed [2,18]. Insects, therefore, had already been processed and consumed in various forms. However, it is important to define and standardize their processing on an industrial scale. Therefore, insect processing parameters (technology, temperature, time) have to be optimized to obtain products of the highest quality and to maximize profitability. The European Union regulates the safety of insect consumption as food or feed with many regulations, e.g., the opinion of the European Food Safety Authority (EFSA) of 8 October 2015, on the risk profile related to the production and consumption of insects as food and feed, Regulation 2283/2015 of the European Commission on novel foods, and Regulation 2017/893 of the European Commission authorising the production of animal protein from insects and recent Regulation 2021/1372 of 17 August 2021 regards the prohibition to feed non-ruminant farmed animals, other than fur animals, with protein derived from animals [19,20,21,22]. In addition, operators who process insects for feed and food purposes must meet specific hygiene requirements for the entire production process and the logistics chain (e.g., GHP and HACCP). Additionally, in the case of the use of insects for feed purposes, insect producers of animal protein for feed must comply with the processing methods provided for in Regulation (EC) 142/2011 or can use any processing method authorized by the competent authority that will fulfill the requirements of the above Regulation. The authorized methods should demonstrate: the identification of relevant hazards in the starting material and of the potential risks in view of the animal health status; the capacity of the processing method to reduce those hazards to a level which does not pose any significant risks to public and animal health; and the sampling of the final product on a daily basis over a period of 30 production days in compliance with specified microbiological standards [23]. Therefore, prior to consumption, insects have to be thermally processed to reduce microbial load and minimize microbiological hazards such as bacteria, parasites, and fungi [24,25]. A combination of freezing, blanching, and drying methods (sun drying, microwave drying, fluidized bed drying, and vacuum drying) are recommended to prolong the shelf life of edible insects and reduce their microbial loads. However, these processes affect the quality of the end product, including water activity, and they induce qualitative and quantitative changes in protein and fat. It has also been shown that various drying methods may reduce the protein solubility, change color, and increase the oxidation of dried mealworms [12,13,18,26,27,28].
Therefore, the use of appropriate technology and parameters of the drying process (e.g., pretreatment, temperature, time) will affect the qualitative and quantitative characteristics of insects. In addition, finding optimal parameters can extend the shelf-life of insects and significantly reduce drying costs. The present study was conducted on the assumption that various drying methods induce changes in the physicochemical composition of mealworm larvae. Therefore, the aim of this study was to determine the extent to which the application of blanching, different drying temperatures and times, and different drying methods influence selected physical and chemical parameters of yellow mealworms.

2. Materials and Methods

2.1. Insect Rearing

Yellow mealworms for drying tests were purchased from Cricketsfarm (Motycz-Józefin, Poland), a commercial supplier of edible insects. The purchased larvae were kept at a temperature of 28 °C and relative humidity of around 60% until analysis. Insects had ad libitum access to chicken feed with the following composition (on a dry matter basis): ash—12.9%, fiber—3.23%, crude fat—2.38%, protein—20.1%. Carrot slices were a source of water, and they were administered according to need, usually around three times a week. Insect drying tests began after the first pupae had emerged in containers.

2.2. Insect Preparation and Drying

In the first test, insects were fasted for 24 h, frass was filtered with a sieve, insects were frozen at a temperature of around −30 °C and stored until further analysis. The prepared insects were dried in a convection oven with a forced air circulation system, at a temperature of 70 °C, 60 °C and 50 °C for 12 h. However, the results were not satisfactory due to the considerable browning of thermally processed larvae (Figure 1). Light-colored larvae (whole insects or meal) are more appealing to consumers. Therefore, the experiment was modified as follows: larvae were immobilized by short-term chilling, and they were blanched (B), dried in a convection oven (T), or freeze-dried (FD).
Insects were fasted for 24 h; frass was filtered out on a 1 mm mesh sieve, and 10 larvae were weighed in triplicate to determine the fresh weight of individual larvae (Table 1). Insect specimens of 100 mL each were immobilized at 4 °C for 2 h before drying. Immobilized insects were blanched in boiling water (10 parts water to 1 part insects) for 60 and 180 s, strained with a sieve, and dried on paper towels. Insect specimens for convective drying were placed on steel trays lined with aluminum foil (to prevent insects from sticking to the metal surface). Insects were dried in two convection ovens (Binder FD53E3, Binder GmbH, Tuttlingen, Germany and Memmert UF750, Memmert GmbH, Schwabach, Germany) with a forced-air circulation system. This procedure allowed us to carry out the experiment at the same time for two different drying times. Parameters for convection drying were temperature: 60 and 80 °C and time: 12 and 16 h. Larvae for the freeze-drying experiment were frozen at a temperature of −20 °C for 4 h and lyophilized (Alpha 1-2 LDplus, Martin Christ Gefriertrocknungsanlagen GmbH, Osterode am Harz, Germany) at −30 °C for 16 h or 24 h (main drying), followed by −40 °C for 2 h (final drying). Dried insects were placed in ziplock bags. Insects were analyzed in four separate batches. The applied drying methods are presented in Figure 2 and Table 1.

2.3. Laboratory Analyses

Larvae were ground in a laboratory mill (Cyclotec, FOSS, Hilleroed, Denmark) with a diameter of 0.5 mm to produce a composite sample. Directly after grinding, the material was placed in tightly sealed glass laboratory containers and stored until analysis. The prepared samples were placed in a TGA THERMOSTEP thermogravimetric oven (Eltra GmbH, Haan, Germany), and their moisture content was analyzed at a temperature of 105 °C (in a nitrogen atmosphere) and ash content—at a temperature of 550 °C (in an oxygen atmosphere). During the process, sample weight was measured continuously to determine weight loss.
Protein content was determined by the Kjeldahl method according to Standard PN-EN ISO 20483. To calculate protein content, the result was multiplied by a nitrogen-to-protein conversion factor of 6.25. Protein content on a dry matter basis was determined based on relative moisture content and protein content on a fresh matter basis. Fat content was determined by extraction with light petroleum according to Standard PN-EN ISO 734-1. Ground samples were placed in extraction thimbles and sealed with cotton wool. The prepared specimens were placed in the Büchi B-811 extraction system (Büchi Labortechnik AG, Postfach, Switzerland) and extracted with petroleum ether into pre-weighed containers. The extraction process (minimum 6 h) was controlled automatically by the device. After the analysis, the containers were dried, weighed, and the percentage fat content was determined on a dry and fresh matter basis. Crude fiber content was determined in the ANKOM A200I system (Ankom Technology, Macedon, NY, USA) with the use of the Weende method. Crude fiber was extracted with 1.25% H2SO4 and 1.25% NaOH. Water activity (aw) was measured using the Rotronic HP-23 (HC2_AW) analyzer (Rotronic AG, Bassersdorf, Switzerland). Insects were ground in a mortar before the measurements, and a ground specimen of 4 g (±0.01 g) was weighed into a measuring cup. Measurements were performed in duplicate at 22 °C (±0.01 °C). The measurement was considered complete when water activity remained constant for at least 10 min.

2.4. Statistical Analysis

Data were processed statistically in the Statistica 13 software package (TIBCO Software Inc., Palo Alto, CA, USA). All analyzed parameters were tested by one-way ANOVA. Arithmetic means and standard deviation were calculated for all parameters. Homogeneous groups were determined in Tukey’s (HSD) multiple comparison test at α = 0.05. The applied drying methods were analyzed by agglomerative hierarchical clustering with the use of Ward’s method, where Euclidean distance was the distance measure. Clusters were identified with the use of the grouping criteria proposed by Sneath. The results of the cluster analysis were used to develop a dendrogram of similarities between larvae dried by different methods. A heat map was also generated for all analyzed parameters of mealworm larvae. In the heat map, original data are subtracted from the sample mean, and the result is divided by the standard deviation of the sample.

3. Results

The results of one-way ANOVA (Table 2) revealed significant differences in all laboratory-analyzed parameters (p < 0.001 for all parameters). Figure 3 presents samples of mealworm larvae after processing. Moisture content was significantly lowest in larvae dried by methods B2T4 (3.15%) and B1T4 (3.22%) (Table 3). Similar moisture content was noted in samples dried by method B1T3 (3.28%). Moisture content was significantly highest in larvae dried by method B1FD1 (5.47%), followed by method B2FD1 (4.79%). The moisture content of the analyzed samples was not always correlated with the water activity (aw) of larvae dried by different methods. Water activity was significantly lowest in sample B1FD2 (0.04), followed by samples B2T4 (0.06) and B2T2 (0.07). Water activity was highest in samples B1FD1 (0.55) and B2FD1 (0.49).
Protein content was significantly highest in larvae dried by methods B1T1 (54.5% DM) and B1T2 (53.7% DM) (Table 3). Protein content was also high in B1FD1 samples (Table 3). The analyzed parameter was significantly lowest in insects processed by method B2FD1 (47.1% DM), and it was only somewhat higher in B2FD2 samples (48.1% DM). Fat content was significantly highest in larvae dried by methods B2T1 (39.9% DM) and B2T3 (39.8% DM), and highly similar values were noted in samples B2T4 (39.7% DM) and B2T2 (39.5% DM). Fat content was considerably lower (30.9% DM) in yellow mealworms processed by methods B1T1 and B1T2, and it was lowest in samples dried by method B1FD1 (29.5% DM).
The analyzed samples also differed significantly in the content of crude fiber (Table 3). Crude fiber content was significantly highest in insects dried by method B1T2 (5.95% DM). The second homogeneous group was formed by insects processed by methods B1T1, B1FD1, and B1FD2, whose crude fiber content was determined in the range of 5.26–5.49% DM. Crude fiber content was significantly lowest in larvae dried by method B2FD1 (4.05% DM).
The ash content of the analyzed samples ranged from 2.77% to 3.55% DM (Table 3). Larvae dried by methods B1FD1, B1T2 and B1T1 were characterized by the significantly highest ash content (3.52–3.55% DM), and these samples formed a homogeneous group. Ash content was significantly lowest in larvae processed by methods B1T3 and B2T2 (2.77–2.80% DM).
Larvae dried by different methods were divided into two distinct groups in the dendrogram generated based on the results of agglomerative hierarchical clustering. The results were additionally interpreted with the use of a heat map (Figure 4). High values of the analyzed parameters were marked in red, whereas low values were marked in green. The first group in the dendrogram was formed by larvae processed by convective drying methods B1T1 and B1T2 as well as larvae that were freeze-dried by method B1FD1. This group was characterized by a high content of ash, protein, and crude fiber, and low fat content. The second group was composed of larvae processed by the remaining drying methods, and it was characterized by a lower content of ash, protein and crude fiber, and high fat content. In both groups, larvae dried by methods B1FD1 and B1FD2 were characterized by considerably higher moisture content and water activity than the remaining samples. Despite the above, these samples did not form a separate group. It should also be noted that larvae forming the first group originated from the first batch of insects, and they were younger and lighter (Table 1) than the larvae dried by other methods, which could explain the differences in their fat and protein content [29,30].

4. Discussion and Conclusions

In most cases, convectively dried yellow mealworms were characterized by lower moisture content than freeze-dried insects. Shorter freeze-drying time (16 h during the main drying, 2 h during final drying) also contributed to high water activity (aw) values (0.49–0.55) and was still sufficient to inhibit microbial growth (suggested aw—0.6) but not sufficient to inhibit enzymatic reactions (aw < 0.4). When freeze-drying time during the main drying was prolonged to 24 h, aw values decreased considerably, in particular in larvae blanched for 60 s. In a study by Lenaerts et al. [13], moisture content was determined at 4.28% in freeze-dried mealworm larvae and at 4.51% in blanched and freeze-dried larvae, whereas the corresponding aw values were determined at 0.36 and 0.18. Kröncke et al. [12] freeze-dried mealworms for 12 and 24 h at a temperature of −50 °C. The first method did not produce satisfactory results (moisture content—15.2%, aw—0.71), but the second approach was effective (moisture content—3.69%, aw—0.25). In the work of Lenaerts et al. [13], freeze-drying time was 52 h (temperature was not shown in this study), and in the study by Kröncke et al. [12], freeze-drying temperature was −50 °C. The results of the present study indicate that freeze-drying time of 24/(2) h and temperature of −30/(−40)°C should be sufficient to inhibit microbial growth as well as enzymatic reactions in dried mealworm larvae. At the same time, the freeze-drying process should be less energy-intensive than the tested methods described above. Moreover, there is still the possibility to find an even more optimal time (between 16–24 h) for larvae freeze-drying that would save energy and reduce cost in industrial drying. The moisture content (3.15–4.07%) and aw values (0.06–0.14) of larvae subjected to convective drying in this study were higher than the values noted in microwave-dried larvae, but these results are satisfactory from the point of view of microbial growth. However, it should be noted that microwave drying has some drawbacks compared to convective and freeze-drying, e.g., lower protein solubility or content of vitamin B12 [12,13].
The protein and fat content of larvae differed significantly between the evaluated drying methods and insect batches. However, the effect of the tested drying methods on the protein and fat content of yellow mealworm could not be reliably established based on these results. Similar observations were made by Lenaerts et al. [13], who reported minor differences in the proximate composition of mealworm larvae dried by different methods. Selaledi and Mabelebele [28] also found that the crude protein content of freeze and oven-dried mealworms were similar, but fat content was differentiated.
Yellow mealworm larvae and other insect species have a high protein content (40–60% DM), which is also confirmed by other studies [18]. However, insects also contain nitrogen chitin, which can be counted as protein nitrogen depending on the nitrogen-to-protein conversion factor used. In our study, we used the factor of 6.25, but other values are suggested and used for insects, such as 4.43–5.75 [31,32]. It was also estimated in recent study that chitin in the mealworm larva body is around 4.92% DM [33].
Lenaerts et al. [13] and Kröncke et al. [12] also found that freeze-dried mealworms had a higher oxidation status than insects dried by other methods. Interesting conclusions were also formulated by Purschke et al. [27]. In the cited study, the tested drying methods significantly influenced the color, dimensions, apparent density, and hardness of mealworm larvae and, consequently, affected the mechanical separation process. In the present study, different drying methods were tested on the same group of larvae, which were reared during the experiment. Interestingly, the youngest and lightest larvae (fresh larval weight—0.101 g; Table 1) dried by methods B1T1, B1T2, and B1FD1 were characterized by the highest content of protein, ash, and crude fiber. These insects were also characterized by the lowest fat content, which could be related to the accumulation of fat in the prepupal stage (Table 3, Figure 4) [29]. Similar observations were made in other species of holometabolous insects [34,35].
In conclusion, this study demonstrated that blanching inhibits enzymatic processes that lead to browning, and larvae have a lighter color that is more appealing to consumers. The moisture content and water activity of dried larvae were significantly affected by the drying method. However, no significant changes in the protein, fiber, or fat content of insects were found when drying parameters were modified, which corroborates the findings of other authors. However, it was noticed that the age of insects significantly influenced the examined larva features. This study will be continued in the future to determine the effect of larval age on the proximate composition of processed mealworms, including the composition of amino acids and fatty acids. Processed insects will also be subjected to microbial analysis to determine the extent to which the tested drying methods reduce microbial loads to produce safe food and feed components that fulfill microbiological requirements.

Author Contributions

Conceptualization, M.K. and M.J.S.; Data curation, M.K. and A.B.; Formal analysis, M.K. and M.A.; Funding acquisition, M.J.S.; Investigation, M.K., M.J.S., M.A. and A.B.; Methodology, M.K. and M.A.; Supervision, M.K. and M.J.S.; Validation, M.K., M.J.S. and M.A.; Visualization, M.K.; Writing—original draft, M.K., M.A. and A.B.; Writing—review and editing, M.K., M.A., M.J.S. and A.B. All authors have read and agreed to the published version of the manuscript.

Funding

This research is the result of a long-term study carried out at the University of Warmia and Mazury in Olsztyn, Faculty of Agriculture and Forestry, Department of Genetics, Plant Breeding, and Bioresource Engineering, topic number 30.610.007-110. The project was financially supported by the Minister of Education and Science in the range of the program entitled “Regional Initiative of Excellence” for the years 2019–2022, Project No. 010/RID/2018/19, amount of funding 12.000.000 PLN. Anna Bordiean has received scholarships under the Interdisciplinary Doctoral Programme in Bioeconomy (POWR.03.02.00-00-I034/16-00) funded by the European Social Fund.

Institutional Review Board Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

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Agriculture 12 00149 g001 550
Figure 1. Larvae from the first drying test at 12 h drying time. Drying temperature from left to right: 70, 60, and 50 °C. Considerable browning of larvae can be observed.
Figure 1. Larvae from the first drying test at 12 h drying time. Drying temperature from left to right: 70, 60, and 50 °C. Considerable browning of larvae can be observed.
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Agriculture 12 00149 g002 550
Figure 2. Diagram of methods applied to dry mealworm larvae.
Figure 2. Diagram of methods applied to dry mealworm larvae.
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Figure 3. Larvae processed during the experiment. From left to right: B1T1, B1T2, B1FD1.
Figure 3. Larvae processed during the experiment. From left to right: B1T1, B1T2, B1FD1.
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Agriculture 12 00149 g004 550
Figure 4. Heat map of drying methods and the analyzed parameters of yellow mealworms.
Figure 4. Heat map of drying methods and the analyzed parameters of yellow mealworms.
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Table
Table 1. Methods applied to dry mealworm larvae and fresh weight of single larvae per batch.
Table 1. Methods applied to dry mealworm larvae and fresh weight of single larvae per batch.
CodeBatch No.Drying MethodBlanching Time (s)Temperature (°C)Drying Time (h)Fresh Weight of Single Larvae (g)
B1T11convective6060120.101
B1T21160.101
B1T3380120.133
B1T43160.133
B2T12convective18060120.122
B2T22160.122
B2T3480120.126
B2T44160.126
B1FD11freeze drying60−30/(−40)16/(2)0.101
B1FD2324/(2)0.133
B2FD12freeze drying180−30/(−40)16/(2)0.122
B2FD2424/(2)0.126
Table
Table 2. Results of one-way ANOVA.
Table 2. Results of one-way ANOVA.
Source of VariationWater ActivityMoistureAshCrude FiberProteinCrude Fat
df11
F12,954754.370.2118.4188.6356.1
p<0.001<0.001<0.001<0.001<0.001<0.001
Table
Table 3. Parameters and composition of mealworm larvae dried by different methods.
Table 3. Parameters and composition of mealworm larvae dried by different methods.
MethodMoisture Content
(%)		Water ActivityProtein
(% DM)		Crude Fat
(% DM)		Crude Fiber
(% DM)		Ash
(% DM)
B1T14.05 ± 0.06 c0.14 ± 0.0 d54.5 ± 0.39 a30.9 ± 0.10 d5.49 ± 0.06 b3.52 ± 0.02 a
B1T24.07 ± 0.04 c0.12 ± 0.001 f53.7 ± 0.48 ab30.9 ± 0.51 d5.95 ± 0.13 a3.52 ± 0.10 a
B1T33.28 ± 0.01 f0.13 ± 0.001 de49.4 ± 0.10 c38.7 ± 0.39 bc4.18 ± 0.09 de2.80 ± 0.11 c
B1T43.22 ± 0.01 fg0.13 ± 0.002 e48.6 ± 0.04 cd39.4 ± 0.13 b4.39 ± 0.14 d2.87 ± 0.02 bc
B2T13.64 ± 0.05 d0.08 ± 0.001 g48.7 ± 0.35 cd39.9 ± 0.29 a4.21 ± 0.08 de2.94 ± 0.11 bc
B2T23.66 ± 0.02 d0.07 ± 0.001 h49.0 ± 0.23 c39.5 ± 0.31 ab4.60 ± 0.11 cd2.77 ± 0.03 c
B2T33.49 ± 0.06 e0.12 ± 0.007 f49.4 ± 0.01 c39.8 ± 0.56 a4.62 ± 0.02 cd3.00 ± 0.03 b
B2T43.15 ± 0.04 g0.06 ± 0.001 h49.4 ± 0.30 c39.7 ± 0.30 ab4.81 ± 0.07 c2.91 ± 0.03 bc
B1FD15.47 ± 0.06 a0.55 ± 0.004 a53.3 ± 0.15 b29.5 ± 0.13 e5.35 ± 0.09 b3.55 ± 0.02 a
B1FD24.08 ± 0.05 c0.04 ± 0.002 i49.4 ± 0.29 c38.4 ± 0.56 bc5.26 ± 0.13 b2.98 ± 0.05 b
B2FD14.79 ± 0.04 b0.49 ± 0.002 b47.1 ± 0.33 e38.0 ± 0.46 c4.05 ± 0.05 e2.98 ± 0.04 b
B2FD24.04 ± 0.01 c0.23 ± 0.001 c48.1 ± 0.17 d37.8 ± 0.17 c4.69 ± 0.08 c2.89 ± 0.04 bc
a, b, c…—letters means that values are statistically different (Tukey’s test at p < 0.05).
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Krzyżaniak, M.; Aljewicz, M.; Bordiean, A.; Stolarski, M.J. Yellow Mealworm Composition after Convective and Freeze Drying—Preliminary Results. Agriculture 2022, 12, 149. https://doi.org/10.3390/agriculture12020149

AMA Style

Krzyżaniak M, Aljewicz M, Bordiean A, Stolarski MJ. Yellow Mealworm Composition after Convective and Freeze Drying—Preliminary Results. Agriculture. 2022; 12(2):149. https://doi.org/10.3390/agriculture12020149

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Krzyżaniak, Michał, Marek Aljewicz, Anna Bordiean, and Mariusz Jerzy Stolarski. 2022. "Yellow Mealworm Composition after Convective and Freeze Drying—Preliminary Results" Agriculture 12, no. 2: 149. https://doi.org/10.3390/agriculture12020149

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