Effects of replacing buttermilk with yogurt acid whey in ranch dressing

Abstract

Greek-style yogurt has expanded from 5 to 50% of the US yogurt market in the past decade, accompanied by a corresponding increase in production of its by-product: yogurt acid whey (YAW). Yogurt acid whey qualities (e.g., low pH, mineral content, astringency, and saltiness) present challenges for processing, disposal, and ingredient use. A shelf-stable ranch dressing was formulated by replacing buttermilk in the control with YAW and concentrated YAW (6.3 to 25.2 °Brix). Added salt, gums, and acids were adjusted. The effects of buttermilk substitution on stability were studied on pasteurized samples (8 mo at room temperature). A consumer sensory study (n = 96) was conducted utilizing hedonic and just-about-right scales. Purchase intent and demographic data were also collected. A focus group (n = 7) evaluated the sensorial attributes of the samples after 6 mo. The experiment was performed in triplicate and all instrumental analyses (pH, soluble solids as °Brix, water activity, refraction index, and color) were conducted in triplicate for statistical analysis. Increasing the gum content in YAW samples resulted in equivalent texture liking compared with the control. Matching the control's NaCl concentration resulted in undesirable higher saltiness. The pH of the 18.9 °Brix YAW ranch sample without lactic acid added was under 4.6, with no effect on flavor liking. Increasing concentrations of YAW decreased L* and water activity, and increased the refractive index and hue. The YAW samples presented minimum changes over 8 mo of storage and had better water retention than the control. We conclude that 15 to 17 °Brix YAW is the optimal replacement for buttermilk in a dressing. The formulation of dressings may be accomplished successfully, sustainably, and cost effectively, with minor processing adjustment, by substituting buttermilk with YAW.