复配稳定剂影响杧果酸奶流变性质的机理研究

Mechanism of Stabilizer Blend on Rheological Properties of Mango Yogurt

为了改善搅拌型杧果酸奶流动输送及贮运过程中的稳定性问题,研究了由海藻酸丙二醇酯(PGA)、乙酰化二淀粉己二酸酯(ADA)、瓜尔豆胶组成的复配稳定剂对搅拌型杧果酸奶流变特性的影响机理。使用L9(34)正交表优化了3种稳定剂的配比,测定了杧果酸奶的感官分值、持水力、流变性质,并观察其微观结构。结果表明:杧果酸奶是一种假塑性流体。当PGA、ADA及瓜尔豆胶的添加质量比为0.03%+0.2%+0.008%时,能最大程度的改善杧果酸奶的品质,且不影响其发酵进程。其感官分值为76.3分,较空白组高出了9.3分;持水力达到了75.57%,较空白组高出了16.17%;滞后面积较空白组减少了272 Pa/s,剪切复原性得到了较大程度的改善;表观粘度较空白组降低了80.8 mPa·s,更为适口;粘度系数K和流动指数n都有所下降,更利于产品的输送。扫描电镜图显示,添加复配稳定剂后,瓜尔豆胶、变性淀粉与蛋白质形成规则的网络结构,稳定了杧果酸奶的凝乳结构,因此改变了杧果酸奶的感官品质及流变学性质。复配稳定剂能有效改善杧果酸奶的稳定性,这为搅拌型热带亚热带水果酸奶的后续研究提供理论和数据基础。

In order to improve the stability of the stirred mango yoghurt during its fluid transportation,storage and transportation,the influence mechanism of stabilizer blend of propylene glycol alginate(PGA),acetylated distarch adipate(ADA)and guar gum on the rheological properties of the stirred mango yoghurt was investigated.The sensory score,water holding capacity(WHC)and rheological properties of the yogurt containing three stabilizers at varying blending ratios were determined using an L9(34)orthogonal array.The results showed that mango yogurt was a kind of pseudoplastic fluid.Adding PGA,ADA and guar gum at a quality ratio of 0.03%+0.2%+0.008%optimally,yogurt quality was improved,and the fermentation process of the yogurt was not affected.After adding optimal quality ratio mixing stabilizer,the sensory score of yogurt was 76.3 points,which was 9.3 points higher than that of the blank group.And the WHC of yogurt reached 75.57%,which was 16.17%higher than that of the blank group.The hysteresis area of the yogurt was reduced by 272 Pa/s compared with the blank group,the shear recovery was improved at a large extent.The apparent viscosity of the yogurt was 80.8 mPa·s lower than that of the blank group,and this maked the mango yogurt more palatable.Both viscosity coefficient K and the flow index n decreased,which was more conducive to product transportation.The scanning electron micrograph indicated that guar gum,modified starch and protein combine to form a network structure after adding stabilizer blend.This stabilized the curd structure of the mango yogurt,and improved the sensory quality and rheological properties of the mango yogurt.The stability of mango yoghurt could be improved by the stabilizer blend,which would provide theoretical and data basis for the follow-up study of the stirred tropical and subtropical fruit yoghurt.