In the heart of volatile compounds of jicaro seeds

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(1)The Food Factor I Barcelona Conference Barcelona (Spain), 2-4 November 2016. The Food Factor I Barcelona Conference Barcelona (Spain), 2-4 November 2016. Improvement of pearl millet protein extractability using various solvent and chromatographic separation. In the heart of volatile compounds of jicaro seeds. R. Bibi1,2, K. Khaladi1,2,*, B.Nadjemi1,3, H. Mokrane1. 1. 1. Laboratoire des produits bioactifs et valorisation de la biomasse (LPBVB), Ecole Normale Sup rieure, Kouba, Alger, Alg rie. 2 Facult des sciences, Universit Benyoucef Benkheda (Alger1), Alger, Alg rie 3 Laboratoire de d veloppement des techniques de traitement et de gestion environnementale, Ecole Normale Sup rieure, BP 92, Kouba, Alger, Alg rie * khaladirafika@yahoo.com. Of all the world's cereals, pearl millet (Pennisetum glaucum (L.) R. Br) is the sixth most important after wheat, rice, barley, maize and sorghum. Pearl millet is the major source of energy and protein for millions of people in many underdeveloped countries in Africa and Asia. Compared to other cereals, greater quantity of pearl millet grains could be produced in short growing season. The objective of this work was to characterize the composition of pearl millet proteins by RP-HPLC. Various extraction methods were assessed including the conventional use of 70% ethanol at 60 C under non reducing or reducing conditions. Three reducing agents were used: %- mercaptoethanol, dithiothreitol (DTT) or sodium metabisulfite at different concentrations. A combination of organic solvent and alkaline extraction was tried.. M. Lebrun1, C. Corrales Hernández1,2, N. Forestier1, I. Maraval, A.M. Perez3, F. Vaillant1, and G. Fliedel1 2 3. CIRAD, UMR QualiSud, F-34398, Montpellier, France UNAN, Facultad de Ciencias Químicas, Ingeniería de los Alimentos, León, Nicaragua Universidad de Costa Rica, Centro Nacional de Ciencia y Tecnología de Alimentos, San José, Costa Rica. In Central America, a popular beverage is made from some roasted oilseeds, named jicaro seeds. Jicaro seeds are numerous and embedded in the pulp of the fruit of jicaro (Crescentia alata H.B.K), a calabash tree, native from Mexico and spread in dry areas of Central America. After fermentation, the seeds are separated from the pulp, sun dried and roasted in order to develop a specific flavor before being ground and used for making the beverage. These seeds are highly valued in several countries of Central America due to their high nutritional value and pleasant aroma. The aim of this study was to understand the effect of roasting on the composition of volatile compounds of jicaro seeds. Qualitative and quantitative determinations of volatile compounds in unroasted and roasted jicaro seeds (140 oC for 140 s) were carried out using Solvent Assisted Flavor Evaporation (SAFE) and Gas Chromatography/Mass Spectrometry (GC/MS).. RP HPLC analysis showed that 70% ethanol+1% DTT +0,4% NaOH at 60 C extracted more millet protein . This new method was more reproducible and more accurate than the other ones tried in this work.. (a). Keywords: Pearl millet; protein; Extraction; RP- HPLC References [1] Hamaker, B. R., Mohamed, A. A., Habben, J. E., Huang, C. P., & Larkins, B. A. (1995). Efficient procedure for extracting maize and sorghum kernel proteins reveals higher prolamin contents than the conventional method. Cereal Chemistry, 72(6), 583-588. [2] [2] Li, Y., Li, J., Xia, Q., Zhang, B., Wang, Q., & Huang, Q. (2012). Understanding the dissolution of -zein in aqueous ethanol and acetic acid solutions. The Journal of Physical Chemistry B, 116(39), 12057-12064.. (b). GC-chromatograms of volatile compounds of (a) unroasted and (b) roasted (140 °C, 140 s) jicaro seeds. A total of 27 volatile compounds were identified and quantified. Styrene appeared to be the main compound with a concentration of 22.57 and 47.0 mg/kg in unroasted and roasted seeds respectively. Many volatile compounds were already found in the unroasted seeds (19 out of 27). Others appeared in roasted seeds such as pyrazines and aldehydes. Most of compound concentrations increased with the roasting process, except for some alcohols or esters. A decrease of some reducing sugars and free amino acids was observed, probably due to Maillard reactions. Additionally, 22 impacting odor compounds of roasted seeds, extracted by Headspace Solid Phase Micro Extraction (HS-SPME), were identified by ten untrained panelists using Gas Chromatography Olfactometry (GCO). Ethyl-2-methylbutyrate was the only one recognized by 100% of the panelists as characteristic of jicaro note with concentrations of 0.16 mg/kg and 0.47 mg/kg in unroasted and roasted seeds respectively, while pyrazines were associated to roasted note. This ester, along with pyrazines, aldehydes, ketones and alcohols, contributes to the specific and pleasant aroma of jicaro seeds and its beverage. Its odor activity value (OAV) was of 1808, with an odor threshold at 0.26 ppb. Keywords: Jicaro seed; roasting process; volatile compounds References [1] Bass, J. 2004. Incidental agroforestry in Honduras: The jicaro tree (Crescentia spp.) and pasture land use. Journal of Latin American Geography 3 (1), 67-80. [2] Amanpour, A., Sonmezdag, A. S., Kelebek, H., & Selli, S. 2015. GC–MS–olfactometric characterization of the most aroma-active components in a representative aromatic extract from Iranian saffron (Crocus sativus L.). Food Chemistry, 182, 251–256. 205. 206.

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