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Ways of valorization of seed jícaro (Crescentia alata) for food security in dry tropical areas of Central America

Abstract : The calabash tree (Crescentia alata) or jicaro is a very important tree in the agro-pastoral systems of the dry tropical regions of America. Its fruits contain many seeds that have traditionally been consumed. However, despite its importance, little information exists on its nutritional properties and its industrial potential.In the first part of this work, the physicochemical characteristics of seeds, cotyledons and coats were analyzed. The cotyledon contains in average 43% protein and 38% lipid (d.b.), which is comparable to most oleaginous seeds. The seed contains no trypsin inhibitors, few phytates and almost no indigestible sugar. A proteomic analysis revealed that proteins are predominantly of low molecular weight (~ 10 kDa) mainly of albumin type 2S, comprising as soybeans up to 16% of essential amino acids. Among lipids, 77.6% are unsaturated fatty acids, mainly oleic acid.As it is a seed traditionally consumed after roasting, this unit operation was studied. For the first time, a volatile compound characteristic of its aroma, and whose content increases as a result of roasting, the ethyl-2-methylbutyrate, has been identified by gas chromatography-olfactometry (GC-O). Yet, other aroma compounds such as pyrazines and certain aldehydes also contribute to the specific and pleasant aromatic notes which are found after roasting. This thermal operation induces physical and microstructural changes, including the coalescence of fat globules, which was observed by scanning microscopy, and puffing which is at the origin of the opening of the seed coat.This last change has been exploited for the dehulling of the seed in order to isolate the white cotyledon. This operation was optimized regarding the color and the number of opened seeds with a kinetic modeling, obtaining an opening rate of more than 90% with a loss of luminance of less than 10%. After roasting, a tempering treatment was carried out to harden the cotyledon and obtain better dehulling efficiency.The isolated cotyledons can be used for the manufacture of a vegetable milk which has physicochemical, sensory and nutritional characteristics superior to many vegetable milks present on the market. A preliminary analysis showed that the milk contains more than 6% lipids and 4% protein and maintains the white color of the cotyledons and the characteristic aroma of jicaro. Clinical studies have also revealed that the obtained milk has a low glycemic index (11). This confirms its potential as a healthy alternative for a lactose-free milk with no anti-nutritional factors and a low glycemic index.
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Submitted on : Thursday, June 28, 2018 - 3:39:05 PM
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Carla Corrales. Ways of valorization of seed jícaro (Crescentia alata) for food security in dry tropical areas of Central America. Food and Nutrition. Montpellier SupAgro, 2017. English. ⟨NNT : 2017NSAM0008⟩. ⟨tel-01825749⟩

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