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• Basic Research •     Next Articles

Comparison of Antioxidant Properties between Yak Milk and Holstein Milk Hard Cheese

  

  • Received:2019-06-20 Revised:2020-06-30 Online:2020-08-15 Published:2020-08-19
  • Contact: LIANG Qi E-mail:liangqi@gsau.edu.cn

Abstract: Objective: explore and reveal the rules of milk fat oxidation and improve the theory of milk fat oxidation of hard cheese by comparing milk fat content and oxidation rate of hard cheese from yak milk and holstein milk. Methods: the acidity value (ADV), carbonyl value (CV), peroxidation value (POV) of primary oxidation degree and thiobarbituric acid value (TBA) of secondary oxidation degree were measured at 4℃ for 0, 1, 2, 3, 4, 5 and 6 months of ripening separately. Results: 1) the ADV value and CV value of the two kinds of cheese increased continuously during the ripening process. For yak milk cheese, the increase of ADV value was (263.94±13.88)%, which was lower than that of holstein ((363.91±11.71)%). The average growth rates of CV of the two kinds of cheese were 0.140 0 ±0.017 7 meq/(kg·month) and 0.138 5 ±0.015 1 meq/(kg·month), respectively. 2) the POV value of primary oxidation rate first increased and then decreased during the maturation period. Except for 3-month ripening (P < 0.05), there were no significant difference in the rest of the maturation period (P > 0.05). 3) TBA value of secondary oxidation showed an upward trend in the maturation process; The total increase of TBA was (330.48±72.64)% and (335.89±36.41)%, respectively. The average growth rates of the two kinds of cheese were 0.035 4 ±0.002 9 mg/(kg·month) and 0.033 6 ±0.002 0 mg/(kg·month) respectively. 4) the regression equations of first and second order oxidation rate of yak milk hard cheese were fitted by calculation, Respectively, Y= -0.001 7x5 + 0.038 2x4 - 0.336 6x3 + 1.347 7x2 - 2.146 7x + 1.496 9 (r2 = 0.993 2);Y= 0.0343x + 0.0244 (r2 = 0.968 8). Conclusion: During the ripening process, yak milk hard cheese exhibits a high milk fat and low oxidation rate. This indicates that the antioxidant factor in yak milk cheese is higher than that of Holstein cow's milk cheese and plays an important role in the late stage of ripening, which inhibits the oxidation rate.

Key words: hard cheese, lipid oxidation, increase of oxidation index, average growth rate

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