The chemical compositions of papaya (Carica papaya L.) fruits were studied under two maturity stages unripe and ripe. the moisture content was found to be 92.78 and 90.7 % , the total acidity 0.187 and 0.125 %, the electro conductivity (E.C.) 0.084 and 0.103%, the pH value was found to be 4.72 and 5.59, ash 0.637 and 0.468% , crude protein 4.75 and 2.88%, total lipids 1.31 and 1.15% , crud fiber 10.53 and 7.41% , total carbohydrates 73.22 and 75.51%, total soluble sugar 9.57 and 9.97 % , reducing sugar 5.87 and 6.90% , non reducing sugar 3.70 and 3.06%, total carotenoids 5.06 and 8.29 mg/100g, ascorbic acid 49.77 and 79.19 mg/100g, total phenols 11.25 and 14.70 mg/100g, total free amino acid 7.9 and 10.11 mg/100g, alcohol insoluble sugar 2.61and 2.01% and pectic substances 0.620 and 0.477% in the unripe and ripe fruits respectively. Also, the results showed insignificant differences in Na, Ca, Mg, Zn and Fe between the both maturities stages (unripe and ripe), while there are significant differences in K and P.
The protein content and proteolytic activity was found to be 0.74mg/ml and 7.68 U/ml of papain enzyme, 0.48mg/ml and 2.8 U/ml of papaya pectinesterase, respectively. The optimum NaCl concentration on PE activity was found to be 0.3M. The optimum pH on the reaction activity of crude papain and papaya pectinesterase was found to be 6.4 and 7. The optimum temperature was found to be 60oC and 55oC respectively. The optimum enzyme concentration was found to be 0.6g/100ml and 12ml of the extract, respectively. The optimum substrate concentration was found to be 1.1g/100ml and 6.5 mg/ml. The Michaelis –Menten constant and maximal rate of the crude papain and papaya pectinesterase were determined as Km, 0.43 g/100ml buffer solution and Vmax 13.68 U/ml, Km 3.2 mg/ml and Vmax 15.6 U/ml respectively.
Biological evaluation of aqueous and ethanol extract of papaya fruit pulp were carried out on male albino rats. It was found that these extracts had a significant effect on liver functions and kidney functions, lipids profile and antioxidant markers comparing with control group. Histopathological examination indicated the aqueous or ethanol extract of papaya fruit pulp treatment at different doses led to minimization the harmful effect of CCl4 on liver and kidney organs.
Key words: Papaya fruits- proximate analysis- papain enzyme- pectinesterase enzyme- papaya extracts.
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