Physicochemical and Functional Properties of Chinese Jujube (<i>ziziphus jujube</i> mill.) Seeds Protein Concentrate

Abstract

About 8 million tons of jujube pomace arise within a year in China. Bioconversion of food processing residues is receiving increased attention because these residual materials represent a possible and utilizable resource for conversion into useful products. To explore the application of Chinese jujube (Ziziphus jujube Mill.) seeds protein concentrate (ZPI ) in food industry, its physiochemical and functional properties were analyzed in this study. The free sulfhydryl content of ZPI is 7.1 × 10 _ 6 mol/g of protein at pH 8.0. Differential scanning calorimetry analyses showed that ZPI had only one endothermic peak with denaturation temperature of about 91℃. Amino acid analyses revealed that ZPI exhibited high levels of glutamic acid, aspartic acid and arginine. The least gelation concentration (LGC) of ZPI is ~8% at pH 7.0, whereas the protein solubility, emulsifying activity, emulsion stability, and waterholding capacity of ZPI were much lower than those of soybean protein concentrate (SPI). These results suggest that ZPI could be used as a valuable source of protein and gel.Keywords: Chinese jujube seed protein concentrate (ZPI), amino acid composition, physiochemical property, functional property IntroductionJujube (Zizyphus jujube Mill.), which is mainly distributed in tropical and subtropical regions of the world, is a tree of the Rhamnaceae family (Li et al., 2007;Mukhtar et al., 2004;Su et al., 2005). Jujube is a popular and profitable fruit, and is much admired due to its high nutritional value. Thus, Chinese jujube has been commonly used in traditional Chinese medicine and also used as food for thousands of years. The Chinese share of world jujube production is about 90% and its production has increased in the last ten years due to the demands for food and pharmaceutical applications (Li et al., 2005;Su et al., 2005), with a total yield of 36 million tons in 2008 (MOA, 2009. About 80% of the annual Chinese jujube production has been consumed in fresh, dried forms and juice, and therefore ~8 million tons of jujube pomace arise annually. These wastes pose potential disposal and pollution problems along with loss of valuable biomass and nutrients.Bioconversion of food processing residues is receiving increased attention because these residues represent a possible and utilizable resource for conversion into useful products. In this context, the utilization of wastes of fruit processing as a source of functional ingredients is a promising field (Schieber et al., 2001 Material and MethodsMaterials Chinese jujube seeds (Ziziphus jujube Mill.) were obtained from Henan Haoxiangni Co., Ltd. Dried soybean (Glycine max) seeds were obtained from the local market. All reagents used in the present study were of analytical grade or better grade.Preparation of seed protein concentrate About 1.0 kg of jujube seeds or soybean seeds were soaked in distilled water overnight and homogenized in four volumes of an aqueous buffer (50 mM phosphate buffered saline (PBS), 1% polyvinylpolypyrrolidone, pH 9.0) using a Waring blender...

Ziziphus lotus (L.) Lam. plant treatment by ultrasounds and microwaves to improve antioxidants yield and quality: An overview

“…Besides containing a higher amount of secondary metabolites, both seed and fruit reveal the presence of important minerals such as magnesium, calcium, and potassium 1 . These compounds are valued for their contribution to a healthy diet and also as ingredients for designing new foods 34,35 . Among the most isolated compounds from Z. lotus (L.), the phenolic acids due to considerable amounts of caffeic acid, gallic acid can be mentioned 34,35 .…”

“…These compounds are valued for their contribution to a healthy diet and also as ingredients for designing new foods 34,35 . Among the most isolated compounds from Z. lotus (L.), the phenolic acids due to considerable amounts of caffeic acid, gallic acid can be mentioned 34,35 . Flavonoids like rutin, epicatechin, taxifolin, and catechin can be extracted with organic solvent or mixtures in all parts of the jujube tree.…”

“…However, the triterpenic acids, abundant in leaves, were proposed to be the main active ingredients for the effect on anti-inflammatory and anticancer activities 37 . While, proteins are found in seeds and pulps known for their functional properties such as emulsifying activity, emulsion stability, and water holding capacity 34 . However, the major organoleptic characteristics of plant-derived food (color, taste, ...) are represented in particular by phenolic compounds 38 .…”