Quality characteristics and consumer acceptance of yogurt fortified with date fiber

Abstract 

Yogurt is considered a healthy food and incorporating dietary fiber will make it even healthier. Date fiber (DF), a by-product of date syrup production, is a good source of dietary fiber. The effect of fortification with DF on fresh yogurt quality was investigated. Acidity, pH, color [L* (lightness), a* (redness), and b* (yellowness) values], texture profile, sensory properties, and consumer acceptance were studied. Control yogurt (without fiber), yogurt fortified with 1.5, 3.0, and 4.5% DF, and yogurt with 1.5% wheat bran (WB) were prepared. Fortification with DF did not cause significant changes in yogurt acidity, although pH was increased. Yogurts fortified with DF had firmer texture (higher hardness values) and darker color (lower L* and higher a*) compared with control or WB yogurts. Consumer test results indicated that the appearance, color, and flavor ratings were significantly affected by fiber fortification. Yogurt fortified with up to 3% DF had similar sourness, sweetness, firmness, smoothness, and overall acceptance ratings as the control yogurt. Sensory ratings and acceptability of yogurt decreased significantly when increasing DF to 4.5% or using 1.5% WB. Flavoring yogurt fortified with 4.5% DF with vanilla did not improve flavor or overall acceptance ratings. Thus, fortifying yogurt with 3% DF produced acceptable yogurt with beneficial health effects.

Key words: yogurt, date fiber, sensory quality, acceptability