Nonfat Set Yogurt: Effect of Okra Gum and Various Starches on the Rheological, Sensory, and Storage Qualities and Wheying-Off

Abstract

This work was intended to determine the effect of okra gum in combination with various starches on the flow and sensory properties of nonfat set yogurt. The selected starches include potato (PS), sweet potato (SPS), corn (CO), chickpea (CP), and Turkish beans (TB). The control is the yogurt prepared with okra gum only. Samples were analyzed under optimum conditions for their shear viscosity, viscoelasticity, texture, wheying-off, and sensory evaluation. Tests were performed at the beginning of the cold storage and after 7 or 15 days. By adding 1.0% starch, significant (p<0.05) reduction in wheying-off and firmer yogurt was obtained. Variations in the properties of yogurt were obvious and can be attributed to starch origin and amylose content. Therefore, the qualities of yogurts with tuber starches (PS and SPS) were different compared to corn or legume starches (CP and TB). The effect of the starches on yogurt properties changed over storage time, where some starches performed better only at the beginning of the storage period, and steady pH was maintained throughout the storage time. Wheying-off was significantly reduced irrespective of the origin of the starch. Sensory evaluation showed preference for yogurts prepared with starch compared to the control, regardless of starch type. Nonetheless, CP was preferred over other starches with respect to wheying-off, power law parameters, and overall acceptability.

Rheological, textural, and sensory properties of non-fat yogurt containing cress (Lepidium sativum) seed gum and various starches

“…However, the LVR of each yogurt sample was dependent on the type of starch added. Similar dependent behavior for LVR was also observed by Saleh et al (2020a).…”

“…The control sample had the softest gel at 0 days and became firmer with increased storage time at a low temperature. In a previous study, yogurt containing CPS alone or in combination with okra pod gum showed a greater G' than yogurt containing tuber starches (Saleh et al, 2020a). Together, these findings indicate that all of the yogurt gels attained time-dependent firmness after 7 days of storage, which was clearly portrayed by the higher G' and increased physical gaps among samples in the profiles.…”

“…However, the control sample (with no additives) had a higher crude protein content and lower total carbohydrate content than the test samples. Similarly, Saleh et al (2020a) reported that the addition of okra (Abelmoschus esculentus) gum and various starches to yogurt did not result in any significant changes in its proximate composition. In terms of the amylose contents of the starches, CPS had the highest content (32.2%), followed by SPS (22.9%) and CS (20.4%), while TBS had the lowest content (17.5%).…”

“…To maintain the quality and organoleptic properties of nonfat yogurt, various additives are included as stabilizers, such as starch, pectin, gelatin, gums, and mucilages (Saleh et al, 2020a;Saleh et al, 2020b;Yu et al, 2016). The shear viscosity profiles of the yogurt samples plotted as the shear rate vs. shear stress are presented in Figure 1.…”

Pasting and Rheological Properties of Different Starches Using Starch Cell of Discovery Hybrid Rheometer

“…The starches are produced from different sources, including cereals like corn, rice, wheat, sorghum, barley, oat (40-90%), tubers like potato, sweet potato (65-85%), roots like tapioca, arrowroot (30-70%), legumes like chickpea, kidney beans, peanuts (25-50%) and some immature fruits like banana and mangoes (up to 70%) [3]. The starches are used in their native or modified form in different food products as thickening, stabilizing, foaming, texturizing, and bulking agents [4,5]. Properties of starches may vary depending on their origin, processing method, form, amylose and amylopectin ratio, chain length, granule size and shape.…”