刺梨发酵乳的制备及其理化性质比较

Preparation and Physicochemical Properties of Roxburgh rose Yogurt

摘要:

刺梨含有丰富的多糖和维生素C 等营养成分以及超氧化物歧化酶（SOD），具有降低慢性疾病风险及发病率的潜力。该研究选用保加利亚乳杆菌德氏乳杆菌DMLD-H1（Lactobacillus delbrueckii DMLD-H1，简称H1）和嗜热链球菌DMST-H2（Streptococcus thermophilus DMST-H2，简称H2）为发酵剂菌株，通过优化菌种比例、接种量和刺梨汁添加量，确定刺梨发酵乳最佳发酵工艺，并与商业菌种发酵的发酵乳的各项理化性质进行比较。实验表明，最佳的刺梨发酵乳发酵条件为：菌种比例为H1:H2=1:2，接种量为1.0×107 CFU/mL，刺梨添加量为0.06 g/mL。在此条件下发酵所得的刺梨发酵乳pH值为4.47，酸度为76.78 °T，持水力为32.94%，其中分离出11种挥发性物质，蛋白质相对分子质量主要分布在22~38 ku，后酸化4 周后发酵乳的pH值降低至3.89，活菌数含量为1.1×108 CFU/mL。对比商业发酵乳发现，刺梨发酵乳能够抑制发酵乳的后酸化作用，提高持水力，以及提升发酵乳中的酪蛋白含量；然而，刺梨可能会影响发酵乳中原本的风味物质。该研究为一种新型的刺梨发酵乳的开发提供理论依据，为新型功能性发酵乳的研发提供参考。

Abstract:

Roxburgh rose is rich in nutrients such as polysaccharides and vitamin C as well as superoxide dismutase (SOD), and has the potential to reduce the risk and incidence of chronic diseases. In this study, Lactobacillus delbrueckii DMLD-H1 (H1) and Streptococcus thermophilus DMST-H2 (H2) were selected as the fermentation starters. By optimizing the strain ratio, inoculation amount and the addition amount of Roxburgh rose juice, the optimal fermentation process for preparing Roxburgh rose yogurt was established. The physicochemical properties of the resulting Roxburgh rose yogurt were then compared with those of the yogurt produced using commercial strains. The results showed that the optimal fermentation conditions for Roxburgh rose yogurt were as follows: H1:H2=1:2; inoculation amount, 1.0×107 CFU/mL; Addition amount of Roxburgh rose juice, 0.06 g/mL. The pH value of the Roxburgh rose yogurt obtained under such conditions was 4.47, with its acidity being 76.78 °T, and the water-holding capacity being 32.94%. From such a yoghurt, 11 volatile substances were isolated, and the relative molecular masses of proteins were mainly in the range of 22~38 ku. The pH value of the yogurt decreased to 3.89 and the viable bacterial count was 1.1×108 CFU/mL after 4 weeks of post-acidification. After comparison with the commercial yogurt, it was found that the Roxburgh rose yogurt was able to inhibit yoghurt’s post-acidification, improve the water-holding capacity, and increase the casein protein content of the yogurt; However, the Roxburgh rose may affect the original flavour substances in the yogurt. The study provides a theoretical basis for the development of a new type of Roxburgh rose yogurt and a reference for the development of new functional yogurts.