Fermented dairy products and their component bacteria have been shown to possess health-promoting functions in consumers and recently have been suggested to reduce the risk of colorectal cancer. Kefir and ayran are two popular fermented milk drinks that have their origins in the Caucasus region of Russia. The present study aimed to evaluate their potential anticancer properties in colon cells in vitro. The comet assay and transepithelial resistance assay were used to assess the effect of kefir and ayran supernatants on genotoxicity of fecal water samples and on intestinal tight junction integrity. Their antioxidant capacity was measured by trolox equivalent antioxidant capacity assay and compared with that of unfermented milk. The results showed that DNA damage induced by 2 of 4 fecal water samples was significantly decreased by kefir and ayran supernatants and with ayran the effect was dose-dependent. However no effect on intestinal tight junctions was observed. The supernatants of kefir and ayran contained high amounts of acetic and lactic acid but only a very small quantity of caproic and butyric acid, and they showed significantly greater antioxidant capacity than milk. These findings suggest kefir and ayran can reduce DNA damage, which might be due to their antioxidant capacities.

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A nonreagent method for the regulation of the pH of acid whey was investigated at a laboratory scale. Acid whey and concentrated acid whey were subjected to electrodialysis with bipolar membranes in order to raise the pH value to 6.5. Demineralised whey underwent identical processing. The deacidification rate as per tonne of a dry matter was similar for acid whey and concentrated acid whey treatment at 70% and 90% degrees of demineralisation. We estimated the energy consumption of electrodialysis. The preliminary demineralisation of whey significantly increased the energy efficiency of whey pH correction. Additionally, we observed substantial fouling on the diluate side of bipolar membranes after whey treatment.

Adverse environmental conditions are severely limiting the use of microorganisms in food systems, such as probiotic delivery, where low pH causes a rapid decrease in the survival of ingested bacteria, and mixed-culture fermentation, where stepwise changes and/or metabolites of individual microbial groups can hinder overall growth and production. In our study, model probiotic lactic acid bacteria (L. plantarum ATCC 8014, L. rhamnosus GG) and yeasts native to dairy mixed cultures (K. marxianus ZIM 1868) were entrapped in an optimized (cell, alginate and hardening solution concentration, electrostatic working parameters) Ca-alginate system. Encapsulated cultures were examined for short-term survival in the absence of nutrients (lactic acid bacteria) and long-term performance in acidified conditions (yeasts). In particular, the use of encapsulated yeasts in these conditions has not been previously examined. Electrostatic manufacturing allowed for the preparation of well-defined alginate microbeads (180–260 µm diameter), high cell-entrapment (95%) and viability (90%), and uniform distribution of the encapsulated cells throughout the hydrogel matrix. The entrapped L. plantarum maintained improved viabilities during 180 min at pH 2.0 (19% higher when compared to the free culture), whereas, L. rhamnosus appeared to be less robust. The encapsulated K. marxianus exhibited double product yields in lactose- and lactic acid-modified MRS growth media (compared to an unfavorable growth environment for freely suspended cells). Even within a conventional encapsulation system, the pH responsive features of alginate provided superior protection and production of encapsulated yeasts, allowing several applications in lacto-fermented or acidified growth environments, further options for process optimization, and novel carrier design strategies based on inhibitor charge expulsion.

A large amount of crystalline lactose is produced globally. The major source for lactose production is the ultrafiltration permeate of sweet whey. However, some other rich in lactose sources are available in the dairy industry such as ultrafiltration permeates of milk or acid whey. Although lactose remains the most abundant component in all ultrafiltration permeates, their composition can differ considerably. Specifically, large variations in the content of lactate, citrate, phosphate, and calcium are observed. Modern technology of lactose purification is optimized for the processing of feed with low acidity. Lactic acid cannot be sufficiently removed from acid whey ultrafiltration permeate, i.e. the latter is poorly processable with current techniques. However, a toolbox of industrial purification methods offers alternative ways to refine dairy fluids with high lactic acid or calcium content such as acid whey ultrafiltration permeate. Here we discuss the variety of processes that yield ultrafiltration permeates and present a proximate composition of permeates obtained from different sources in the dairy industry. The methods suitable for the purification of ultrafiltration permeate solutions within the framework of lactose manufacture are reviewed in the paper. We also share our vision on how lactose production can be adapted to the processing of ultrafiltration permeates with high lactic acid content.