Supplementation of Beverage, Yogurt and Probiotic Fermented Milk with Lentil Flour and Pea Flour and Study of their Microbial, Physical and Sensory Properties after Production and During Storage.

摘要

1-4% of pulse fractions including pea protein and fiber, chickpea and lentil flour as well as soy flour and protein concentrate were selected and characterized. As preliminary results the functional properties of pulse ingredients are varied upon their protein content and pH of the food carrier. Orange juice, apple juice, yogurt and two probiotic fermented milk were selected for supplementation. 1% and 2% pulse fractions gave comparable results in terms of turbidity, cloud and visual stability, color and sensory attributes for both orange and apple juices beverages. All supplements improved the acidification rate of yogurt and probiotic cultures, but the highest effects were obtained with probiotic supplementation with lentil and soy flour. As for the main study, skim milk (9.5 % w/v solid content) was supplemented with 1-3% (w/v) lentil flour, pea flour or skim milk powder and they were inoculated with yogurt starter cultures or probiotic (L. rhamnosus). Acid production during the fermentation, the pH, syneresis, color, rheological properties (dynamic oscillation temperature sweep test at 4-50 °C), and sensory properties (only for yogurt) were studied after production and 28 days of refrigerated storage.1-3% lentil and pea flour enhanced acid production during yogurt fermentation, but the microbial population (CFU) of both S. thermophilus and L. bulgaricus were in the same range in all lentil and pea flour and skim milk supplemented yogurts, after production. Pea flour supplementation enhanced survival of L. bulgaricus after storage. The pH decreased from 4.5 to 4.1 in lentil flour and from 4.5 to 3.75 in pea flour supplemented yogurts, after 28 days. Syneresis in 1-2% lentil and pea flour supplemented yogurts was higher than other samples. In lentil supplemented yogurts, "a" and "L" values did not significantly differ in all samples and remained constant after 28 days whereas, "b" value increased as a result of supplementation. Pea flour supplementation did not alter redness or greenness of yogurts, but the yellowness was significantly higher than other yogurts. Yogurt with 3% lentil and pea flour had higher storage (G') and loss (G'') moduli in comparison with samples supplemented with 1-3% skim milk and the control yogurt. 1-2% lentil and pea flour supplemented yogurt showed comparable sensory properties in comparison with 1-2% skim milk supplemented and control samples.1-3% lentil and pea flour enhanced acid production during probiotic fermentation, and the CFU's of L. rhamnosus were comparable with non-supplemented control sample after production. After 28 days, the CFU`s of 2% and 3% lentil supplemented probiotic were as high as 1% skim milk supplemented sample and the CFU`s of 3% pea flour supplemented probiotic was the highest followed by 3-2% skim milk and 1-2% pea flour supplemented samples. The pH decreased from 4.50 to 3.90 for lentil flour supplemented probiotics and from 4.50 to 4.04 for pea flour supplemented probiotics, over 28 days. Syneresis in 1-3% lentil and pea flour supplemented probiotic was significantly lower than other samples. All lentil flour supplemented samples had significantly lower "L" values and higher "b" and "a" values in comparison with skim milk supplemented samples. Pea flour supplementation slightly changed the color which was not as light as skim milk supplemented samples and they showed more yellowness in final product after production and storage. Probiotic fermented milk with 1-3% lentil and pea flour showed higher G' and G'' in comparison with other samples.