Microbial viability and nutritional content of water kefir grains under different storage conditions.

Water kefir grains are an important source of probiotics, mainly containing lactic acid bacteria and yeasts. The aim of this study is to investigate the changes in microbial and chemical properties of water kefir grains during 1-month storage at +4°C and -18°C. The initial content of lactobacilli, lactococci, and yeast in water kefir grains was 6.06, 6.33, and 5.93 log CFU/g, respectively. The number of lactobacilli, Lactobacillus acidophilus, and Bifidobacterium spp. in the water kefir grains were comparable, with slight changes at the end of refrigerated storage (p > .05). Lactococci and yeasts decreased significantly after both storage conditions compared to the initial content (p < .05). The dry matter and ash contents remained unchanged during storage (p > .05). Water kefir grains contained significant amounts of calcium, vitamin B2, vitamin B6, vitamin B7, and vitamin B12. Storage at both +4°C and -18°C did not affect the mineral and vitamin contents, except for Cu and Vitamin B2. The results indicate that the water kefir grains remained viable after storage at both temperatures. If water kefir grains need to be stored, it is recommended to store them at +4°C in sugared water as it ensures better survivability of the microbiota of the grains.

Use of mandarin and persimmon fruits in water kefir fermentation.

Water kefir is a non-dairy probiotic beverage. It is obtained by fermentation of water kefir grains with a sugar solution. This study aims to determine the properties of water kefir beverages obtained by fermentation of mandarin and persimmon-containing water for 42 h. According to microbiological results, both fruits containing water samples provided a high number of lactic acid bacteria and yeasts. Moreover, after fermentation, pH, Brix, and dry matter content did not significantly differ. On the other hand, fructose, maltose, and acetic acid contents of mandarin water kefir are significantly higher than persimmon water kefir (p < .05). Persimmon water kefir had higher total phenolic contents, twice as much as mandarin water kefir (p < .05). Both water kefirs had good color properties. The organoleptic acceptability of the fruit water kefirs was promising.

Water kefir grains vs. milk kefir grains: Physical, microbial and chemical comparison.

AIMS: Although kefir has been known for centuries, there is confusion between the two types of kefir grains, for example, milk kefir (MK) grain and water kefir (WK) grain. This study aimed to unravel the differences and similarities between WK grain and MK grain. METHODS AND RESULTS: Microbiological analyses, identification of grains microbiota and enumeration of microbiological content of the grains as well as scanning electron microscope (SEM) imaging, dry matter, protein, ash, and mineral content, and colour analyses were carried out for the two types of grains. As a result, significant differences were found in microbiological content, chemical properties and colours (p < 0.05). Additionally, SEM images revealed the different intrinsic structures for the microbiota and the structure of the two types of grains. CONCLUSIONS: MK grain has more nutritional content compared to WK grain. Despite not as widely known and used as MK grain, WK grain is a good source for minerals and health-friendly micro-organisms such as lactic acid bacteria and yeasts. WK grain is possibly suitable for vegans and allergic individuals to fulfil nutritional requirements. Moreover, in this study, the variety of WK grain microbial consortia was wider than that of MK grains, and this significantly affected the resultant WK products. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study that comprehensively compares two different kefir grains in microbial, chemical and physical properties.

Volatile aroma compounds and bioactive compounds of hawthorn vinegar produced from hawthorn fruit (Crataegus tanacetifolia (lam.) pers.).

This study was aimed to produce of hawthorn vinegar to increase the usage area and consumability of the hawthorn fruit and benefit from its functional properties, and to reveal some bioactive compounds, occurred during vinegar production, the functional properties and the volatile compounds (VC). The results showed that the gallic acid was a prominent phenolic substance in both wine and vinegar, followed by the chlorogenic acid. The prominent VACs of the hawthorn vinegar were acetic acid, phenylacetic acid, acetoin, then, respectively, pentanoic acid, benzoic acid, (E)-isoeugenol, 2-cyclohexenone, propanoic acid, chavicol, and diethyl succinate. Within this study, hawthorn vinegar was produced as a new product that had a favorable volatile aroma compound profile and phenolic compounds with high bioactivity. Hawthorn vinegar that shown as an alternative way for the use of hawthorn fruit, its of whose functional and aromatic aspect was first revealed in detail. PRACTICAL APPLICATIONS: Hawthorn is a seasonal fruit, which has potential to be economically important. It has rich bioactive compounds known to have a positive effect on health. However, organoleptic properties (astringent, grainy texture, etc.) of fresh hawthorn fruit are not be mostly liked among most of the consumers. This situation prevents benefiting from the positive effect of hawthorn fruit. For this reason, in this study, it was aimed to produce the hawthorn vinegar, which economically more valuable and also, more functional than fresh hawthorn fruit. According to the results of the present study, organoleptic, functional, and economic values of the hawthorn fruit were improved with the hawthorn vinegar produced in result of the fermentation process. So, it has been considered that this study is beneficial for consumers, scientist or food industry professionals as it guides to transform a low-economic food product to highly economic and functional food product.

The changes of physicochemical properties, antioxidants, organic, and key volatile compounds associated with the flavor of peach (Prunus cerasus L. Batsch) vinegar during the fermentation process.

Peach is a delicious food preferred by consumers and widely used in the manufacture of peach juice, peach juice concentrate, peach jam, dried fruit, puree, etc. Alternatively, peach can be used in the production of vinegar. In this study, peach vinegar was produced as an alternative to other industrial products produced from peach. In this study, it was determined that the TPC content and ORAC value of peach vinegar were higher than those of peach juice and peach wine. In addition, the major contributor compounds to the aroma profiles of the samples were the γ-decalactone, linalool, and geraniol compounds for the peach juice; the ethanol, ɣ-decalactone, phenylacetic acid, acetic acid, 2-phenylethanol, ethyl decanoate, the linalool, and the decanoic-acid for the peach wine; and the ɣ-decalactone, phenylacetic acid, acetic-acid, phenethyl-acetate, and isovaleric acid for the peach vinegar. It is thought that the results of this study will pave the way for the widespread production of vinegar from peach, which has positive effects on health, is rich in volatile aroma components, and has a high potential to be preferred. Furthermore, this study is the first detailed study so far on peach vinegar. PRACTICAL APPLICATIONS: In this study, it was aimed to produce vinegar as a new and alternative foodstuff product from peach fruit which was normally processed as fresh or/ dried fruit, fruit juice, puree, and canned fruit by the industry. An alternative idea was created for the use of peach fruit, which has a short shelf life. In the study, the antioxidant capacity, organic compounds, and volatile compounds associated with aroma profile of peach vinegar during the fermentation process were determined. Moreover, the changes of these compounds were monitored during the fermentation process. The results of the study are a guide for the usability of peach fruit as a raw material in the production of peach vinegar, which has potentially positive effects on health, is rich in volatile aroma components, and has a high potential to be preferred. Furthermore, this study is the first detailed study on peach vinegar.

Horizon Scanning: How Will Metabolomics Applications Transform Food Science, Bioengineering, and Medical Innovation in the Current Era of Foodomics?

Food and engineering sciences have tended to neglect the importance of human nutrition sciences and clinical study of new molecules discovered by food engineering community, and vice versa. Yet, the value of systems thinking and use of omics technologies in food engineering are rapidly emerging. Foodomics is a new concept and practice to bring about "precision nutrition" and integrative bioengineering studies of food composition, quality, and safety, and applications to improve health of humans, animals, and other living organisms on the planet. Foodomics signals a three-way convergence among (1) food engineering; (2) omics systems science technologies such as proteomics, metabolomics, glycomics; and (3) medical/life sciences. This horizon scanning expert review aims to challenge the current practices in food sciences and bioengineering so as to adopt foodomics and systems thinking in foodstuff analysis, with a focus on possible applications of metabolomics. Among the omics biotechnologies, metabolomics is one of the prominent analytical platforms of interest to both food engineers and medical researchers engaged in nutritional sciences, precision medicine, and systems medicine diagnostics. Medical and omics system scientists, and bioengineering scholars can mutually learn from their respective professional expertise. Moving forward, establishment of "Foodomics Think Tanks" is one conceivable strategy to integrate medical and food sciences innovation at a systems scale. With its rich history in food sciences and tradition of interdisciplinary scholarship, the Silk Road countries offer notable potential for synthesis of diverse knowledge strands necessary to realize the prospects of foodomics from Asia and Middle East to Europe.