为了探究牛乳与豆乳配比对酸奶理化性质、流变学特性、微观结构和感官特性的影响,将不同质量配比(100∶0、75∶25、50∶50、25∶75、0∶100)的牛乳与豆乳混合,加入1 g/L直投式发酵剂,在43 ℃条件下发酵至pH = 4.8,在4 ℃条件下贮存并进行分析。结果表明,随豆乳比例的增加,酸奶中蛋白质含量增加,脂肪含量降低。与纯牛乳酸奶相比,混合乳酸奶的发酵时间缩短,持水力降低,储能模量和损耗模量增加;纯豆乳酸奶的持水力、储能模量和损耗模量居中。纯牛乳或纯豆乳制备的酸奶具有光滑规整的微观结构,混合乳酸奶微观结构粗糙,有大量的微孔。整体上,50%牛乳和50%豆乳制备的酸奶在28 d贮存期内具有良好的风味、较高的感官分数和贮存稳定性。
Effects of the ratio of cow milk to soymilk on the physicochemical, rheological, microstructural and sensory properties of yogurt were investigated. Different ratios of cow milk to soymilk (100∶0, 75∶25, 50∶50, 25∶75, 0∶100) were mixed and fermented with 1 g/L direct vat set starter culture at 43 ℃ until pH dropped to 4.8, and then stored at 4 °C for analysis. With an increasing ratio of soymilk, the protein content in yogurt increased and the fat content decreased. The combination of cow milk and soymilk shortened the fermentation time. The water holding capacity were lower, the storage modulus and loss modulus were higher in yogurts produced from mixtures than that fermented from cow milk only, and these values in yogurt produced from soymilk were intermediate among them. Yogurts produced with solely cow milk or soymilk had a smooth microstructure, whereas the structure of yogurts produced with mixtures of cow milk and soymilk was coarse with numerous micropores throughout. Yogurt prepared from 50% cow milk and 50% soymilk had a suitable beany flavor, and high sensory score and stability during 28 d of storage.
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