Characterization of Kefir Produced in Household Conditions: Physicochemical and Nutritional Profile, and Storage Stability

Abstract

Kefir, a traditional fermented food, has numerous health benefits due to its unique chemical composition, which is reflected in its excellent nutritional value. Physicochemical and microbial composition of kefir obtained from fermented milk are influenced by the type of the milk, grain to milk ratio, time and temperature of fermentation, and storage conditions. It is crucial that kefir characteristics are maintained during storage since continuous metabolic activities of residual kefir microbiota may occur. This study aimed to examine the nutritional profile of kefir produced in traditional in use conditions by fermentation of ultra-high temperature pasteurized (UHT) semi-skimmed cow milk using argentinean kefir grains and compare the stability and nutritional compliance of freshly made and refrigerated kefir. Results indicate that kefir produced under home use conditions maintains the expected characteristics with respect to the physicochemical parameters and composition, both after fermentation and after refrigerated storage. This work further contributes to the characterization of this food product that is so widely consumed around the world by focusing on kefir that was produced in a typical household setting.

Homemade Kefir Consumption Improves Skin Condition—A Study Conducted in Healthy and Atopic Volunteers

“…It was determined that 100 mL of the prepared kefir had a nutritional composition of 1.28 ± 0.04 g of fat, 3.15 ± 0.19 g of protein and 4.91 ± 0.19 g of carbohydrates and 0.6 g of lactic acid. Microbiologically, it provided 7 × 10 9 colony-forming units (CFU) of LAB and 2 × 10 8 CFU of yeast [27], which is consistent with the literature for the daily ingestion of probiotic bacteria capable of surviving passage through the gastrointestinal tract and thus reaching the necessary sites to exercise their positive physiological functions, both intestinal and immunological [58,59].…”

“…Microbiological characterization, preservation, and storage of these grains have been described elsewhere [55][56][57]. Kefir was produced by fermentation of a commercial ultra-high temperature pasteurized (UHT) semiskimmed cow milk of Portuguese provenance (Nova Açores ® , S. Miguel, Portugal), with CIDCA AGK1 kefir grains using a grain inoculum of 10% (w/v), for 24 h, at a temperature of 20 ± 1 • C. The fermentation conditions were designed to be representative of Portuguese household conditions, as described elsewhere [27]. In order to assure the daily intake of kefir for eight consecutive weeks, each subject of both intake groups (AK or HK) visited the research center three times a week (Monday, Wednesday and Friday).…”

“…During the visit, the subjects drank 100 mL of kefir and were given white plastic sterile containers with the kefir doses of the following days. The subjects were instructed to store these kefir samples in their household refrigerator to maintain their characteristics [27]. It was determined that 100 mL of the prepared kefir had a nutritional composition of 1.28 ± 0.04 g of fat, 3.15 ± 0.19 g of protein and 4.91 ± 0.19 g of carbohydrates and 0.6 g of lactic acid.…”

“…Kefir is one of the most ancestral fermented foods with probiotic characteristics [20][21][22][23]. Traditionally prepared by the fermentation of milk with kefir grains and most popular in northeastern Europe and Asia, it consists of a symbiotic mixture of lactic acid bacteria (LAB) and yeasts that, in addition to acting synergistically, also produce several bioactive compounds [24][25][26][27]. A wide variety of health-promoting benefits have been associated with its use [28][29][30][31][32][33] and have expanded its popularity beyond its traditional borders within northeaster Europe and Asia.…”

The Emerging Scenario of the Gut–Brain Axis: The Therapeutic Actions of the New Actor Kefir against Neurodegenerative Diseases

“…The origin of fermented milk goes back to antiquity, most likely when man began to use animal milk in his food. Caucasians discovered that fresh milk carried in leather bags (animal skins) could occasionally ferment, resulting in a fizzy drink [ 151 ] whose shelf life was longer than that of raw milk [ 152 ]. The Bible also describes a product similar to kefir, called “manna”, as a food that was miraculously produced, being provided by God to the Israelite people, led by Moses, during his stay in the desert toward the promised land (Exodus 16), which justifies the term “prophet’s drink” [ 153 , 154 ].…”