TITLE:
Survival of Lactobacillus acidophilus in Fruit-Flavored Greek Yogurt Acid Whey
AUTHORS:
Alexis Dufrene, Dasom Park, Douglas Olson, Kayanush Aryana
KEYWORDS:
Acid Whey, Lactobacillus Acidophilus, Greek Yogurt, Whey Beverage, Pro-biotic
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.12 No.7,
July
13,
2021
ABSTRACT: Greek yogurt has become much more popular within the last 15 to 20 years.
The by-product of Greek yogurt manufacture is acid whey. Although acid whey has
been considered a waste product, researchers are exploring various uses of this
whey. Since the health benefits of consuming probiotics are widely known, one
may propose adding probiotics to acid whey to form a probiotic beverage. Typically,
probiotic bacteria do not thrive in acidic conditions. It would be beneficial
to determine if the probiotic Lactobacillus acidophilus can survive in
these acidic conditions. The objectives were to determine the growth of L.
acidophilus in acid whey resulting from manufacturing Greek yogurt and to
study any changes in apparent viscosity, pH, and titratable acidity over 4
weeks of refrigerated storage. Plain yogurt was manufactured, and whey was
separated from plain yogurt to yield Greek yogurt and acid whey. Acid whey was
batch pasteurized, cooled, sweetened, flavored with pineapple flavoring,
inoculated with L. acidophilus, and stored at 4°C for 4 weeks. The log L.
acidophilus counts progressively decreased from 7.84 immediately after
manufacture to 2.06 at week 4. There were no significant changes in pH and
titratable acidity of the pineapple-flavored probiotic acid whey over 4 weeks
of storage, indicating product stability over shelf life. Viscosity changed
over the storage time with minimum values at week 2 and maximum values at week
4. Although the counts declined over 4 weeks of storage, some L. acidophilus survived in the pineapple-flavored acid whey.