Neltuma genus, whose species belong in the recent past to Prosopis genus [1], is recognized for its ecological resilience and economic potential. Diverse Neltuma species all around the world are employed in various cultures as food ingredient for bread, or other meals, for their nutritional value and good sensory acceptability [2–5]. Neltuma spp. stands out as a promising contributor to sustainable food solutions, aligning with the global initiatives aimed at addressing food security and promoting biodiversity conservation as established by the Food and Agriculture Organization (FAO) within the Sustainable Development Goals (SDGs).
Neglected and underutilized species (NUS) are wild, cultivated or semi-domesticated, non-commodity, crops non-commercial crops that do not fall under conventional agriculture [6]. They are used for food, medicine, trading, or cultural practices that are significant within their local communities but are not widely commodified or studied as part of the conventional agriculture and survive only in small local or niche markets. However, since they are economically viable, and locally available or adaptable, they may contribute to tackling food and nutrition insecurity and climate change vulnerability [6]. According to FAO experts working for the SDG of zero hunger, NUS have been prioritized as Future Smart Food and have a central role to play in the fight against hunger and malnutrition [7]. The use of wild fruits is part of the application of dynamic local knowledge, sensitive to social and ecological changes [8].
Plants from genus Neltuma (ex Prosopis) are considered NUS, since they are wild species, mainly underutilized. Neltuma species belong to the economically important family Fabaceae (or Leguminosae). It includes many species native to the Americas, distributed from the southwestern and central United States through Mexico, Central America, the Caribbean, and South America to southern Argentina. When Spanish arrived in America name Neltuma plants as carob their similarities with the European carob (Ceratonia siliqua), also from the Fabaceae family.
Fabaceae plants are a healthy and affordable source of protein and provide excellent nutritional support to humans and animals. Also, the presence of nodules that contain symbiotic nitrogen fixing Ryzobium bacteria is remarkable characteristic of leguminous plants, and they play a key role in crop rotation [9]. However, unlike other species in this family (beans, soybeans, peas, chickpeas, peanuts, lentils, lupins, mesquite, alfalfa, fenugreek, clove and guar), Neltuma species are NUS and do not have an established or formally defined commercial value. Although they are underutilized and barely studied, relegated by research or development efforts, they hold a perceived potential to contribute to nutrition, food security, genetic resistance, or sustainability, since they could have a positive impact on the conservation of native forests and regional economies [8, 10], thus preserving biodiversity. According to Hughes et al. (2022), some of the more abundant species of this genus are Neltuma alba (Griseb.), N. nigra (Griseb.), N. chilensis (Molina), N. flexuosa (DC.) and N. affinis (Spreng.), Neltuma caldenia (Burkart) commonly known as white carob, black carob, tamarugo, sweet carob or alpataco, ñandubay and caldén, respectively [1].
Many of the Neltuma species are endemic in Argentina and they are also extremely resistant to adverse environments (heat, drought, alkalinity, and salinity). They contribute to soil stabilization and improvement, allowing sustainable agriculture [11, 12]. Since their development provides numerous ecologically desirable characteristics, many projects are based on carob trees for the recovery of soils since due to its highly branched root system, it constitutes a protector against erosion [13–15]. The sustainable use of this sub-valuated resource also represents a source of income for the native populations of arid and semiarid areas of South America and other regions of the world and an opportunity for innovation for the food industry [16]. Several works have been published on the collection of pods of different species of the genus and on their use in the manufacture of flour, bread, syrup, lodge, as medicine or as substitute for chocolate or coffee, confirming its importance [17–21]. Due to the limited research efforts devoted to the NUS species and their characterization, it is important to identify the compounds present in selected vegetable extracts and quantify them in order to avoid variations for climate, species, or cultivar.
Neltuma ruscifolia (Griseb.) (commonly called vinal, visnal, viñal, olkhá, pao de espinho, quilín, tayt and yuncumarim) is comparatively less documented and even more underutilized, in comparison to others species of its genus [1]. Their fruits (pods) are made up of an external part, the exocarp, fibrous in nature, which surrounds the mesocarp or pulp (composed mainly of sugars) and the endocarp (the capsules) also fibrous and much harder than the exocarp. Within the capsules the seeds contain high protein content of good nutritional and good level of fibers [5, 22]. Remarkably, these latter authors proposed alternatives for wheat bread making employing N. ruscifolia flours in a batter formulation. Their high protein content makes it suitable for human and livestock consumption as well as to enrich other flours [22]. An interesting feature of leguminous plants is the presence of a polysaccharide in their seeds, many of them with many potential technological applications. The physico-chemical and rheological characterization of the galactomannan gum extracted from the endosperm of vinal (Neltuma ruscifolia) seeds, which is similar to guar gum, have been performed [21, 23–25].
In recent decades, plants phenolic compounds have attracted considerable attention due to their functional and nutritional benefits, including antioxidant and antimicrobial effects. The activitity of polyphenols to counteract lipid oxidation, which is one of the main causes of food deterioration, is well known. Besides, polyphenols may block dicarbonyl compounds generated in the Maillard reaction thus avoiding protein glycation, and those that meet this condition are potential antiglycating agents [26]. Extracts rich in these compounds offer a promising solution to replace artificial additives, meeting the rising consumer demand for natural food products and cleaner labels. The extraction of compounds from natural sources with potential technological application plays a pivotal role in various scientific domains, and extraction should be conducted in optimized “green” or environmentally friendly techniques. These methods not only reduce the environmental impact but also enhance the extraction efficiency, yielding extracts rich in beneficial compounds from many vegetal species, as has been reported for green pepper [27], Prosopis alba and P. nigra [28], and N. juliflora [29].
The primary objective of this study is to assess the antioxidant and antiglycation properties of extracts obtained from various extraction methods and milling fractions of Neltuma ruscifolia pods. Additionally, the research aims to identify the associated bioactive compounds and pinpoint the fractions exhibiting the highest concentration of these compounds and utilize these findings in the development of ingredients that enhance the diversification of food sources and contribute to a more sustainable agri-food system.