Lactic Acid Bacteria Production From Whey

Screening for Antifungal Indigenous Lactobacilli Strains Isolated from Local Fermented Milk for Developing Bioprotective Fermentates and Coatings Based on Acid Whey Protein Concentrate for Fresh Cheese Quality Maintenance

The demand for healthy foods without artificial food additives is constantly increasing. Hence, natural food preservation methods using bioprotective cultures could be an alternative to chemical preservatives. Thus, the main purpose of this work was to screen the indigenous lactobacilli isolated from fermented cow milk for their safety and antifungal activity to select the safe strain with the strongest fungicidal properties for the development of bioprotective acid whey protein concentrate (AWPC) based fermentates and their coatings intended for fresh cheese quality maintenance. Therefore, 12 lactobacilli strains were isolated and identified from raw fermented cow milk as protective cultures. The safety of the stains was determined by applying antibiotic susceptibility, haemolytic and enzymatic evaluation. Only one strain, Lacticaseibacillus paracasei A11, met all safety requirements and demonstrated a broad spectrum of antifungal activity in vitro. The strain was cultivated in AWPC for 48 h and grew well (biomass yield 8 log10 cfu mL−1). L. paracasei A11 AWPC fermentate was used as a vehicle for protective culture in the development of pectin-AWPC-based edible coating. Both the fermentate and coating were tested for their antimicrobial properties on fresh acid-curd cheese. Coating with L. paracasei A11 strain reduced yeast and mould counts by 1.0–1.5 log10 cfu mL−1 (p ≤ 0.001) during cheese storage (14 days), simultaneously preserving its flavour and prolonging the shelf life for six days.

Invited review: Acid whey trends and health benefits

In recent years, acid whey production has increased due to a growing demand for Greek yogurt and acid-coagulated cheeses. Acid whey is a dairy by-product for which the industry has long struggled to find a sustainable application. Bulk amounts of acid whey associated with the dairy industry have led to increasing research on ways to valorize it. Industry players are finding ways to use acid whey on-site with ultrafiltration techniques and biodigesters, to reduce transportation costs and provide energy for the facility. Academia has sought to further investigate practical uses and benefits of this by-product. Although modern research has shown many other possible applications for acid whey, no comprehensive review yet exists about its composition, utilization, and health benefits. In this review, the industrial trends, the applications and uses, and the potential health benefits associated with the consumption of acid whey are discussed. The proximal composition of acid whey is discussed in depth. In addition, the potential applications of acid whey, such as its use as a starting material in the production of fermented beverages, as growth medium for cultivation of lactic acid bacteria in replacement of commercial media, and as a substrate for the isolation of lactose and minerals, are reviewed. Finally, the potential health benefits of the major protein constituents of acid whey, bioactive phospholipids, and organic acids such as lactic acid are described. Acid whey has promising applications related to potential health benefits, ranging from antibacterial effects to cognitive development for babies to human gut health.

Effect of milk phospholipids on the growth and cryotolerance of lactic acid bacteria cultured and stored in acid whey-based media

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Acidification activity is retained by adding milk phospholipids to acid whey-based medium

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Retention of activity (as rate of lactic acid production) is relevant to cryoprotection studies

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Acid whey from cottage cheese production is a good medium for preserving frozen cultures

Increasing interest in foods beyond their nutritional value has promoted the development of various novel functional foods that could convey multiple health benefits to consumers. The application of lactic acid bacteria (LAB) and milk phospholipids (MPL) in combination has shown some amplifying effects on the health benefits provided by both ingredients. Freezing is commonly used in LAB preservation and storage. However, the freezing/thawing process damages cell membranes and leads to a loss in viability and functionality of LAB. This study aimed to investigate the influence of MPL on growth and cryotolerance of LAB using acid whey-based medium (AWM) supplemented with 0.5% MPL. Fourteen LAB strains were initially screened from 124 LAB using acid whey-based medium (AW). We then evaluated the cell viability and acidification ability, using the plate counting method and skim milk fermentation test, respectively, of the 14 strains cultured in AW and AWM before and after 3 cycles of freezing/thawing. The presence of 0.5% MPL in AWM significantly promoted the growth of LAB. Supplementing the culture and storage medium with 0.5% MPL significantly enhanced the resistance of selected LAB to freeze-thaw cycles in terms of cell viability and acidification ability. These results suggest that supplementing with 0.5% MPL might promote the growth of LAB and enhance the cryotolerance of LAB cultures in fermented dairy products. This finding leads to a better understanding of the synergistic effects contributed by the LAB–MPL combination and promotes the development of new LAB–MPL functional products.

Production of chlorothalonil hydrolytic dehalogenase from agro-industrial wastewater and its application in raw food cleaning

BACKGROUND

To reduce the fermentation cost for industrialization of chlorothalonil hydrolytic dehalogenase (Chd), agro-industrial wastewaters including molasses, corn steep liquor (CSL) and fermentation wastewater were used to substitute for expensive carbon and nitrogen sources and fresh water for lab preparation.

RESULTS

The results showed that molasses and CSL could replace 5% carbon source and 100% organic nitrogen source respectively to maintain the same fermentation level. Re-fermentation from raffinate of ultra-filtered fermentation wastewater could achieve 61.03% of initial Chd activity and reach 96.39% activity when cultured in a mixture of raffinate and 50% of original medium constituent. Typical raw foods were chosen to evaluate the chlorothalonil removal ability of Chd. After Chd treatment for 2 h at room temperature, 97.40 and 75.55% of 30 mg kg^-1 chlorothalonil on cherry tomato and strawberry respectively and 60.29% of 50 mg kg^-1 chlorothalonil on Chinese cabbage were removed. Furthermore, the residual activity of the enzyme remained at 78-82% after treatment, suggesting its potential for reuse.

CONCLUSION

This study proved the cost-feasibility of large-scale production of Chd from agro-industrial wastewater and demonstrated the potential of Chd in raw food cleaning. © 2016 Society of Chemical Industry.

Probiotics production and alternative encapsulation methodologies to improve their viabilities under adverse environmental conditions

Probiotic products are dietary supplements containing live microorganisms producing beneficial health effects on the host by improving intestinal balance and nutrient absorption. Among probiotic microorganisms, those classified as lactic acid bacteria are of major importance to the food and feed industries. Probiotic cells can be produced using alternative carbon and nitrogen sources, such as agroindustrial residues, at the same time contributing to reduce process costs. On the other hand, the survival of probiotic cells in formulated food products, as well as in the host gut, is an essential nutritional aspect concerning health benefits. Therefore, several cell microencapsulation techniques have been investigated as a way to improve cell viability and survival under adverse environmental conditions, such as the gastrointestinal milieu of hosts. In this review, different aspects of probiotic cells and technologies of their related products are discussed, including formulation of culture media, and aspects of cell microencapsulation techniques required to improve their survival in the host.

High-pressure reactivity of L,L-lactide

L,L-Lactide, a dimer of L-lactic acid, is the typical monomer used for the catalytic synthesis of poly(L-lactic acid) (PLLA). We studied its phase diagram and reactivity at high pressure and high temperature by means of a diamond anvil cell. FTIR and Raman spectroscopy were employed to probe the changes occurring in the sample. An increase of temperature at pressure higher than 0.1 GPa revealed a solid-solid phase transition before the melting. A reaction was observed immediately after the melting with the almost complete transformation of the starting reactant to an amorphous poly(lactic acid) (PLA). The increase of pressure was found to accelerate the process, suggesting the reaction rate to be limited in the diffusion step. A steeper acceleration, likely due to multiphoton absorption processes of the 647.1 nm laser light by PLA, was observed in the Raman experiments.