Nutritional Interest of Geoffroea decorticans “Chañar”: A Native Species from the Province of Mendoza, Argentina ^†

Abstract

The “chañar” (Geoffroea decorticans) is a tree native to the drylands of South America, historically valued for its nutritional, medicinal, and energy-providing properties. The significance of this species lies in its adaptation to conditions of water and salt stress, as well as its tolerance to wide thermal fluctuations, making it a candidate for utilization in climate change adaptation strategies. This study aimed to quantify the nutritional and mineral contributions of G. decorticans fruits from the province of Mendoza, Argentina. Representative specimens were selected, and the fruits were manually harvested for an analysis. The moisture and energy contents were determined using official analytical techniques. The evaluation of the nutritional components was conducted on a dry weight basis, including the total mineral, protein, fat, and total carbohydrate contents. In the mineral fraction test, nitrogen, phosphorus, potassium, sodium, calcium, and magnesium were quantified. The results revealed an adequate protein content (5.27 ± 0.06%) and elevated levels of crude fiber (19.27 ± 0.46%) and total carbohydrates (85.53 ± 0.98%). A high fiber content contributes to satiety, and its consumption could significantly enhance the population’s dietary reference intake. Although the mineral profile appears satisfactory, further investigation is required to clarify the factors affecting the bioavailability of each element. Even though there are existing studies on the variation of nutritional properties across different geographic regions, no local studies were identified. This research provides valuable data for the revaluation of ancestral species with nutritional significance, especially considering the growing trend towards the use of native plants in gastronomy.

1. Introduction

Geoffroea decorticans (Gillies ex Hook. and Arn.) Burkart is a species native to South America, belonging to the botanical family Fabaceae. It is commonly found in the drylands of Argentina, northern Chile, Bolivia, southern Peru, the Paraguayan Chaco, and western Uruguay. In Argentina, it has a broad distribution, ranging from Jujuy to the northern Patagonia [1].

It inhabits dry environments with low precipitation, at altitudes ranging from 100 to 2600 m a.s.l., across different edaphic conditions but generally in fine-textured soils, which are often prone to flooding or salinity. Within its natural distribution range, isolated specimens can be observed, or they may form closed groves, supported by its strong gemmiferous roots, which also enable it to colonize new areas. This behavior characterizes it as a pioneering species, crucial for biodiversity conservation [2]. Its adaptation to water and salt stress, as well as large thermal fluctuations, confers productive potential under climate change scenarios. The availability of this species in nurseries specialized in native flora demonstrates its capacity for domestication and cultivation, promoting its propagation while preventing the degradation of natural habitats.

Commonly known as “chañar”, this tree has been traditionally and extensively utilized by indigenous peoples and rural inhabitants. Locally, its wood is used in the manufacture of furniture, household items, tool handles, and as fuel due to its energetic properties. The leaves and bark (which has dyeing properties) are employed in traditional medicine. Its fruit contains a sweet and pasty pulp, rich in carbohydrates and fibers, which provides significant nutritional potential and has been used ancestrally both for food and as fodder [3]. It can be consumed fresh or used as an ingredient in various recipes, including sweet foods (“arrope”) and alcoholic ferments (“aloja”).

The use of pre-Hispanic plants in culinary preparations has recently gained international prominence, highlighting the need for rigorous botanical and nutritional characterization. In this context, the aim of this work was to determine the nutritional and mineral composition of G. decorticans fruits from the province of Mendoza, Argentina, as a contribution to the development of local gastronomy.

2. Materials and Methods

2.1. Study Area

Fruit collection was conducted in Montecaseros District, General San Martín Department, Mendoza, Argentina, in an area on the boundary between grapevine crops and natural vegetation [4]. The climate is desertic, with an average annual temperature of 15 °C, average annual precipitation reaching 200 mm during the spring-summer period, and an average altitude of 620 m a.s.l. The vegetation in the natural environment corresponds to the classic Monte Phytogeographic Province, recently classified within the Septentrional District [5], where evergreen shrub steppes and shrublands predominate, along with small relics of forests and grasses in open areas with low tree and shrub cover. The soils are poorly developed Entisols, characterized by a strong moisture deficit for most of the year and predominance of sandy textures, with frequent fixed and semi-fixed dunes and availability of groundwater.

2.2. Botanical Description of G. decorticans

G. decorticans is a tree that can reach up to 10 m in height (Figure 1). Its most distinctive feature is its bark; grayish, it sheds in discontinuous, longitudinal, and irregular plates and strips, revealing the new bright green tissue underneath, which provides photosynthetic activity and a unique appearance (Figure 2). The leaves are pinnate, deciduous, and gray-green, ranging from 1 to 7 cm in length [1]. The flowers are hermaphroditic, measuring 0.8 to 1 cm in length, fragrant, with a striking papilionaceous corolla that is yellow-orange with red stripes. The fruit is a drupaceous legume, measuring 1.5 to 3.5 × 1.5 to 2.4 cm, being ovoid to slightly compressed, glabrous, smooth, and reddish. It generally contains a single seed (exceptionally two), measuring 1.2 to 1.8 cm in length, with a thin reddish testa [2]. In Argentina, flowering occurs in spring, between September and October, depending on the latitude. Fruiting is typically complete during January and February.

2.3. Sampling

Fruit collection was carried out in the study area at the end of summer 2024. Eighteen representative trees were selected randomly, taking into account their satisfactory phytosanitary condition. The fruits were manually harvested and stored in paper bags until the sample preparation stage, which occurred 24 h later.

2.4. Sample Preparation and Chemical Analysis

The sample preparation began with the separation of the whole fruit (Figure 3) into two fractions, the endocarp and seed (S) and mesocarp and exocarp, hereafter referred to as “pulp” (P) (Figure 4). Both fractions were weighed fresh. The mesocarp and exocarp were dehydrated in a forced-air oven until reaching a constant weight. To carry out the analysis, the dehydrated mesocarp and exocarp were ground using a knife grinder to obtain a homogeneous flour (Figure 5). All determinations were performed in triplicate, following official analytical techniques [6,7].

Moisture: Indirect method involving drying in an oven at 70 °C, until a constant weight is achieved (Method of AOAC 167.03 15th Ed. 1990).

Dry material: Method of AOAC 167.03 15th Ed. 1990.

Total fat: Direct method involving extraction with ethyl ether (crude fat) (AOAC 920.39 C 15th Ed. 1990). A Soxhlet gravimetric method was used.

Crude protein: Kjeldahl method (AOAC 984.13 16 Ed. 5th revision 1999), determining nitrogen, using 6.25 as a protein conversion factor.

Ashes: Direct method (AOAC 942.05 15th Ed. 1990) involving incineration in a muffle furnace (at 500 ± 10 °C) until the absence of black spots in the ashes.

Total carbohydrates (including dietary fiber): Determined by difference, using the following formula (Chapter V Argentine Food Code):

100 − (weight in grams [protein + fat + water + ash]), in 100 g of food

Mineral profile: Determined based on the ashes, involving a chemical analysis. Sodium (AOAC 974.01 18th Ed. 1997), potassium (AOAC 974.01 18th Ed. 1997), phosphorus (AOAC 986.24 18th Ed. 1997), calcium, and magnesium (AOAC 968.31 15th Ed. 1990).

2.5. Statistical Analysis

All determinations were performed in triplicate (A, B, and C). The results were calculated on both dry and wet bases and are expressed as average values with standard deviations, using the SPSS^® statistical software v29.

3. Results and Discussion

3.1. Centesimal Composition of the “Chañar” Fruit

The results obtained are presented in

Table 1. Average centesimal composition of chañar fruits.

Nutritional Composition (100 g)	Values Expressed on a Wet Basis	Values Expressed on a Dry Basis
Humidity (g)	15.03 ± 1.72
Dry matter (g)		84.97 ± 1.72
Ash (g)	6.90 ± 0.21	8.12 ± 0.21
Total protein (g)	4.48 ± 0.10	5.27 ± 0.06
Total fat (g)	0.92 ± 0.05	1.09 ± 0.04
Total carbohydrates (g)	72.67 ± 1.64	85.53 ± 0.98

.

The moisture contents of the fresh fruit ranged from 13.67% to 16.97%. This characteristic is advantageous in areas without access to electric preservation methods. The values were higher than those reported by Maschio et al. [8] in the Argentine provinces of Catamarca and Río Negro, which may be attributed to climatic or phenological conditions at the time of collection. The protein content was 4.48%, similar to that of the other two regions, while the caloric value was notably lower. Regarding lipids, the values obtained in Mendoza represented 26% and 15% of those found in Catamarca and Río Negro, respectively. The carbohydrate fraction was the most significant in Mendoza samples (85.53 ± 0.98%), as well as in Catamarca (84.90 ± 7.67%) and Río Negro (81.60 ± 5.23%), with very similar absolute and relative values. To make these values comparable, the sum of the carbohydrates and fibers was considered. The results of the present work are in line with the work of Maschio et al. [8]. These results are also consistent with those presented by Orrabalis [9], who notes that “chañar” is an energy-rich fruit.

3.2. Mineral Composition of the “Chañar” Fruit

The mineral profile is presented in

Table 2. Average mineral composition of chañar fruits.

Mineral Composition (100 g)	Values Expressed on a Wet Basis	Values Expressed on a Dry Basis
Sodium (mg)	31.1 ± 4.5	36.6 ± 5.8
Potassium (mg)	1103.6 ± 22.9	1298.9 ± 0.8
Calcium (mg)	339.6 ± 7.0	399.7 ± 0.3
Magnesium (mg)	247.8 ± 5.1	291.6 ± 0.2
Phosphorus (mg)	100.6 ± 2.0	118.4 ± 3.0

.

Costamagna et al. [10] determined a sodium content of 23 mg Na/100 g, which was slightly lower than the value found for Mendoza. However, in both cases, the sodium content is considered low. The mineral contents obtained from chañar trees in northwestern Argentina contrast with those reported in our study, representing 239% of the potassium, 33% of the calcium, 38% of the magnesium, and 2% of the phosphorus found in Mendoza.

4. Conclusions

This study quantitatively determined the nutritional and mineral compositions of G. decorticans fruits in Mendoza, Argentina. This provides local information on an innovative aspect such as the nutritional contribution of a native forest species. Laboratory analyses revealed characteristics of the chañar that highlight its significance for the food industry, such as its low moisture content (which supports preservation at room temperature without refrigeration until consumption) and adequate levels of proteins, calcium, and magnesium, given their nutritional importance.

The results indicate the need to further investigate the bioavailability of each chemical element and the variability in the synthesis of nutritional compounds. This includes linking these factors with environmental and climatic aspects and promoting this species to diversify and add value to the local gastronomy industry.