Optimization of Protein Extraction from Arachis hypogaea L. and Cucumeropsis mannii Naud. Seeds for Use as Natural Coagulants in Surface Water Clarification

Abstract

The aim of this study was to improve the quality of protein extracts from Cucumeropsis mannii Naud. and Arachis hypogaea L. The evolution of protein content and microbiological quality of aqueous extracts of A. hypogaea, C. mannii and M. oleifera seed powders were monitored over time during protein extraction. The protein contents of the extracts subjected to decantation and those subjected to centrifugation were determined by the Kjeldahl method. The microbiological quality of the different aqueous extracts was evaluated according to the standards NF EN ISO 7932, NF V 08-059 and NF EN ISO 4833-1. The results obtained show protein contents of 40.6 % for A. hypogaea, 25.4 % for C. mannii and 36.5 % for M. oleifera, after 24 h of decantation. The protein contents of the centrifuged aqueous extracts were higher and 55.9%, 36.7% and 37.6% for A. hypogaea, C. mannii and M. oleifera extracts respectively. The results of the microbiological analysis showed that the aqueous extracts of M. oleifera contain little microbial load. Significant growth of aerobic flora and Bacillus cereus was observed in the decanted extracts of C. mannii and A. hypogaea from 4 h to 24 h of decantation. Extracts obtained by centrifugation have a lower microbial load, because the treatment time was shorter. The aqueous protein extracts of A. hypogaea and C. mannii seed powders obtained by centrifugation were of better quality than those obtained by decantation, because they have higher protein contents and lower microbial loads. The water solubility of A. hypogaea and C. mannii seed proteins was also studied on protein suspensions at 2% at pH 3, 4, 5, 6, 7 and 8. The results obtained showed that adjusting the pH to 7 and 8 could improve the degree of protein extraction for A. hypogaea and C. mannii seeds.

Seeds of Citrullus lanatus (Thunb.) Matsum. & Nakai, Vigna unguiculata (L.) Walp. and Zea mays L.: Chemical Characterization of the Coagulating Solutions

“…The results of the protein solubility study of Citrullus lanatus, Vigna unguiculata and Zea mays seeds are presented in Fig. The results obtained with Vigna unguiculata seeds are similar to those obtained for Arachis hypogaea seeds where the solubility of seed proteins reaches 70% at pH 7 and 8 [14]. The native pH values for solutions of the powders of these seeds are 5.60; 5.55 and 5.38 for Zea mays, Citrullus lanatus and Vigna unguiculata respectively.…”

“…As part of the implementation of this goal, we are undertaking investigations on the research of natural coagulants of plant origin, to have scientific data on natural substances of plant origin with coagulant activity; to be able to expand the range of natural coagulants of plant origin and also to contribute to the improvement of water quality for people in rural areas of developing countries [9][10][11]. Our previous work has shown the coagulant activity of aqueous solutions of Arachis hypogaea and Cucumeropsis mannii seed powders in the clarification of surface water samples of initial turbidities 131 NTU, 128,60 NTU, 94 NTU, 91,06 NTU, 89.45 NTU, 41,45 NTU and 32,75 NTU [12][13][14]. They also characterized the proteins in the coagulating solutions of the seed powders in these solutions [13].…”

Nutritional Value and Amino Acid Profile of Dried Seeds of Cucumeropsis mannii (Cucurbitaceae)

“…The proximate composition of Cucumeropsis mannii seed flour was shown in table 1. The percentage protein of 31,80 ± 1,16 was comparable to the value reported for melon seeds (31.1 %) and squash seeds (33.0 %) [16] but lower than the results of C. mannii seeds (37.4-37.9 %) in Nigeria [17,18]. Studies proved that, proteins were essential macronutrients for humans, with a key role in building and repairing the body [19].…”

“…Thus, C. mannii seeds could be classified as oilseeds that can be used as a source of vegetable oil for industrial and domestic purposes. The ash content (3.12 ± 0.38 %) was lower for the values reported for Benincasa hispida seeds (5.02-11.81 %) [26] but similar to M. oleifera seeds (3.5 %) [18]. Therefore, Cucumeropsis mannii seeds could [27]; almost lower to that of peanut (626 Kcal/100g) [28]; but higher with those reported for Cucurbita maxima (438.84 ± 0.07 Kcal/100g DM) [24] in Nigeria.…”