Studies On Factors Influencing Nonenzymatic Browning Of Jujube And The Corresponding Ways Of Controlling

The Chinese jujube (Zizypus jujuba Mill), a special fruit growing in China. The plantation area of Chinese jujube has increased 0.33 million ha, with an annual output of 1.1 billion kg, accounting for 95% of the total world output. As we know, Jujube Mill has a high nutritional value, especially Jujube date contains polysacchride, cyclic, which make Jujube date has all kinds of biological function.The changes of sucrose, reducing sugar, amino acid, ascorbic acid, 5-HMF and A420 in Jujube during heating; the effect of heating temperature, heating time, pH and additive on nonenzymatic browning of Jujube pulp; the inhibiting effect of organic acid, sulphite, glutathione, cysteine and cystine on nonenzymatic brown of Jujube pulp are studied in this paper. The results showed that:1. The sucrose, reducing sugar, amino acid and ascorbic acid in Chinese jujube are easily to brown.2. During heating of Jujube pulp, the changes of 5-HMF follows zero order kinetics while the changes of brown pigment follows first order kinetics. Activation energy values of 28.9469 and 31.5092 kJ/mol are obstained for 5-HMF and brown pigment, respectively.3. During heating of Jujube pulp, pH value decreases. When pH value is 2, Jujube pulp is brownish at once; when it's 3, browning is slightly; when it's 4-6, higher the pH value is, greater the brown becomes.4. 1% and 2% lysine and glycin can accelerate nonenzymatic brown of Jujube pulp. 1% asparagine can inhibit nonenzymatic brown of Jujube pulp.5. Reducing sugar can accelerate nonenzymatic brown of Jujube pulp, the effect of fructose is higher than glucose.6. Cu~2+, Fe~3+ and Fe~2+ can accelerate nonenzymatic brown of Jujube pulp evidently; Mn~2+ and Zn~2+ have slight effect on nonenzymatic brown of Jujube pulp; Al~3+, Sn~2+ and Ca~2+ can inhibit nonenzymatic brown of Jujube pulp.7. Ascorbic acid, citric acid and EDTA can all inhibit nonenzymatic brown of...