Aloe vera enriched kefir production and determination of quality properties during storage

In this study, it was aimed to produce a novel kefir fortified with Aloe vera (Aloe barbadensis Miller) gel. Physical, chemical, rheological, microbiological and sensory properties were determined during storage (1st, 7th, 14th and 21st days). The dry matter, protein, ash, titration acidity, pH and serum separation values of the samples varied between 8.58-10.71%, 2.81-3.87%, 0.51-0.65%, 0.63-0.76%, 4.25-4.35 and 57.15-67.29%, respectively. Samples exhibited pseudoplastic behaviour as a characteristic of non-Newtonian fluids, according to viscosity and rheological analysis results. A decrease occurred in viscosity and flow properties with the Aloe vera gel addition. Total phenolic contents, ABTS and DPPH values changed between 101.31-333.61 mg GAE/L, 83.85-99.47 mg TE/L and 473.51-615.54 mg TE/L, respectively. It was observed that total phenolic contents decreased while ABTS values increased with Aloe vera gel addition. In the GC-MS volatile component analysis, 44 volatile compounds were determined, mainly heptanoic acid ethyl ester, acetoin and acetic acid ethyl ester. 1-Hexanol, benzyl alcohol and 2-methyl pentanoic acid were detected due to Aloe vera gel addition. Total aerobic mesophilic bacteria, yeast-mold, Lactobacillus, Lactococcus, total coliform and Escherichia coli were counted in microbiological analysis and the results were in range with legislation. Sensory analysis was performed and samples had acceptable scores. A symbiotic fermented beverage produced by using Aloe vera gel as a substrate for lactic acid fermentation may have a greater impact on health than individual prebiotics and probiotics. Therefore, industrial production of this novel fermented milk product is recommended.