Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
Instituto de Tecnología de Alimentos y Procesos Químicos (ITAPROQ), CONICET - Universidad de Buenos Aires, Buenos Aires, Argentina.
J Sci Food Agric. 2022 Nov;102(14):6727-6736. doi: 10.1002/jsfa.12040. Epub 2022 Jun 16.
Salad dressing formulations include a pH within 3.2-4.1, salt and other solutes to depress water activity. The interaction between hydrocolloids and other components such as humectants determines their physical and microbiological stability. To our knowledge, the effect of commonly used solutes on physical stability and rheological characteristics of oil-in-water emulsions stabilized by xanthan gum has not been reported, and neither has the effect of a spoilage yeast on physical stability been evaluated.
The effect of different humectants (sodium chloride, glucose and xylitol) and Zygosaccharomyces bailii inoculation on the stability of oil-in-water emulsions containing different levels of xanthan gum to emulate different types of salad dressings was investigated by means of droplet size, zeta potential, rheological measurements and confocal laser scanning microscopy (CLSM). Generally, the addition of humectants strengthened the weak or strong emulsion structure, especially xylitol. Glucose or xylitol acted as stabilizers since they decreased Sauter and De Broucker diameter. On the contrary, NaCl destabilized the emulsions since it increased droplet size and exhibited the lowest absolute values of zeta potential. Inoculation with Z. bailii destabilized some emulsions since it increased Sauter and De Broucker diameter. Emulsion droplet size, polydispersity, and xanthan gum and yeast location were confirmed by CLSM imaging.
This study highlights the key role of humectants and xanthan gum level on physical characteristics and stability of oil-in-water emulsions. Addition of xylitol leads to an enhancement in emulsion rheology and physical stability, suggesting that it is a potential low-calorie multifunctional additive for salad dressings. © 2022 Society of Chemical Industry.
沙拉酱配方的 pH 值在 3.2-4.1 之间，含有盐和其他溶质以降低水活度。水胶体与保湿剂等其他成分之间的相互作用决定了其物理和微生物稳定性。据我们所知，常用溶质对黄原胶稳定的水包油乳液的物理稳定性和流变特性的影响尚未报道，也未评估腐败酵母对物理稳定性的影响。
通过测定液滴大小、zeta 电位、流变学测量和共聚焦激光扫描显微镜（CLSM），研究了不同保湿剂（氯化钠、葡萄糖和木糖醇）和酿酒酵母接种对含有不同水平黄原胶的水包油乳液稳定性的影响，以模拟不同类型的沙拉酱。一般来说，保湿剂的添加增强了弱或强乳液的结构，特别是木糖醇。葡萄糖或木糖醇作为稳定剂，因为它们降低了 Sauter 和 De Broucker 直径。相反，NaCl 使乳液不稳定，因为它增加了液滴大小，表现出最低的 zeta 电位绝对值。酿酒酵母的接种使一些乳液不稳定，因为它增加了 Sauter 和 De Broucker 直径。通过 CLSM 成像确认了乳液液滴大小、多分散性、黄原胶和酵母位置。
本研究强调了保湿剂和黄原胶水平对水包油乳液物理特性和稳定性的关键作用。木糖醇的添加导致乳液流变性和物理稳定性增强，表明它是沙拉酱中一种有潜力的低热量多功能添加剂。© 2022 英国化学学会。
