Production of α-ketoisovalerate with whey powder by systemic metabolic engineering of Klebsiella oxytoca.

BACKGROUND: Whey, which has high biochemical oxygen demand and chemical oxygen demand, is mass-produced as a major by-product of the dairying industry. Microbial fermentation using whey as the carbon source may convert this potential pollutant into value-added products. This study investigated the potential of using whey powder to produce α-ketoisovalerate, an important platform chemical. RESULTS: Klebsiella oxytoca VKO-9, an efficient L-valine producing strain belonging to Risk Group 1 organism, was selected for the production of α-ketoisovalerate. The leucine dehydrogenase and branched-chain α-keto acid dehydrogenase, which catalyzed the reductive amination and oxidative decarboxylation of α-ketoisovalerate, respectively, were inactivated to enhance the accumulation of α-ketoisovalerate. The production of α-ketoisovalerate was also improved through overexpressing α-acetolactate synthase responsible for pyruvate polymerization and mutant acetohydroxyacid isomeroreductase related to α-acetolactate reduction. The obtained strain K. oxytoca KIV-7 produced 37.3 g/L of α-ketoisovalerate from lactose, the major utilizable carbohydrate in whey. In addition, K. oxytoca KIV-7 also produced α-ketoisovalerate from whey powder with a concentration of 40.7 g/L and a yield of 0.418 g/g. CONCLUSION: The process introduced in this study enabled efficient α-ketoisovalerate production from low-cost substrate whey powder. Since the key genes for α-ketoisovalerate generation were integrated in genome of K. oxytoca KIV-7 and constitutively expressed, this strain is promising in stable α-ketoisovalerate fermentation and can be used as a chassis strain for α-ketoisovalerate derivatives production.

DNA-based qualitative and quantitative identification of bovine whey powder in goat dairy products.

As one of the main ingredients in some milk powders, whey powder is sometimes added to pure goat milk products, which can cause health risks, economic fraud, and unfair competition of food industries. This study is the first to explore qualitative and quantitative methods to identify adulteration of bovine whey powder in goat dairy products based on DNA. We extracted DNA from whey powder using a modified DNA extraction method; this exhibited good quality and integrity, with purity of 1.53 to 1.75 and concentration of 122 to 179 ng/µL. Conventional PCR and real-time PCR were compared for qualitative detection of bovine whey powder; real-time PCR demonstrated sensitivity of 0.01 ng/µL, which was higher than the 0.05 ng/µL detected by the conventional PCR method. Furthermore, real-time PCR was conducted for DNA quantitative detection, with good linearity (R2 = 0.9858) obtained for bovine whey powder contents from 0.1% to 30%. Relative error decreased with increase of the mixing proportion of whey powder; the coefficient of variation above 0.1% of the mixing ratio was close to or less than 5%; and the relative standard deviation of repeatability results was less than 5%. Considering the economic costs of testing, conventional PCR could be performed first, and samples with obvious intentional adulteration detected can be further accurately quantified by real-time PCR. Overall, this research provides a realistic and effective method for qualitative and quantitative identification of bovine whey powder in goat dairy products, thus laying a good foundation for verification of goat dairy product label claims and industrial control.

Manufacturing and characterization of whey and stevia-based popsicles enriched with concentrated beetroot juice.

The beet-root (Beta vulgaris) and whey powder together, can potentially use as a multifunctional ingredient in the manufacturing of the "Popsicles", due to their biochemical composition that can enhance the concentration of bioactive compounds. In the present study, beet-root juice concentrates were prepared at different time/temperature treatments viz 45 °C, 55 °C, and 65 °C for 120, 80 and 45 min. The effect of different time/temperature treatments on physicochemical composition, colour, antioxidant activity (%), bioactive compounds, spectral data and sensory acceptance were evaluated. The physicochemical parameters of popsicles (PTI, PT2, PT3) including protein, total phenols, betalain, radical scavenging activity %, colour and melting values were significantly affected (p ≤ 0.05) by the different time/temperature treatments. The concentration of betalain and protein in all the popsicles ranged from 1134 to 1299 mg/L and 1.92 to 1.54 g/100 g respectively. The reduction of bioactive components viz betacyanins, betaxanthins, betanin, oxalic and syringic acid was also observed in popsicle (PTI) as compared to control. Furthermore, popsicle (PT1) was prepared with beet-root juice concentrated at 45 °C showed maximum sensory acceptance. The physicochemical and organoleptic attributes of processed popsicles encourage the commercial usage of whey powder and concentrated beetroot juice.

Effect of dietary supplementation of whey powder and Bacillus subtilis on growth performance, gut and hepatic function, and muscle antioxidant capacity of Japanese quail.

This experiment was conducted to evaluate the effects of dietary supplementation of whey powder (WP), Bacillus subtilis (BAS), and their combination (MIX) on growth performance, intestinal morphology, caecal microflora, hepatic gene expression, blood metabolites, and skeletal muscle antioxidant capacity in Japanese quails. A total of 400 one-day-old Japanese quails were randomly distributed to 20-floor pens (4 dietary treatments, 5 replications per treatment, 20 birds per pen). The birds were fed a basal diet (control, CON) or the basal diet supplemented with 40 g/kg WP, 1 g/kg BAS probiotic or 40 g/kg WP plus 1 g/kg BAS probiotic for five weeks. Feed intake was not affected by the treatments at any stage of the trial. However, the WP, BAS, and MIX feed had better weight gain and feed conversion ratio compared to the CON during the entire production period (day 1-35; p < .05). Feeding the WP, BAS, and MIX diets caused no significant difference in morphometric measures in the duodenum, jejunum, and ileum other than the villus height to crypt depth ratio in the ileum (p < .05). The expression of insulin-like growth factor-1 (IGF-1) and growth hormone genes was highly upregulated in the liver of the birds fed the MIX diet (p < .05). Feeding birds with the diets containing WP, BAS, and MIX increased the population of caecal lactic acid bacteria and reduced serum cholesterol concentration compared to the CON diet (p < .05). Likewise, the tested feed additives increased superoxide dismutase and glutathione peroxidase enzyme activities in the thigh muscle (p < .05). No synergistic effect was found between WP and BAS in studied parameters other than IGF-1 gene expression. Improved growth performance of Japanese quails by feeding the WP, BAS, and the MIX feed could be linked to improved absorptive capacity of the small intestine as well as over-expression of anabolic growth factors. In conclusion, WP with or without BAS could be considered as a beneficial dietary supplement to enhance productive performance, gut functionality, and antioxidant capacity of Japanese quail.

Bacteriocin production by Lactobacillus plantarum ST16Pa in supplemented whey powder formulations.

Whey, the main by-product of the dairy industry, is frequently disposed of in the environment without any treatment due to the high cost of this process. Alternatively, whey can be used as a medium to culture lactic acid bacteria and produce value-added products such as bacteriocins. In this work, we attempted to improve bacteriocin production by Lactobacillus plantarum ST16Pa in a whey powder formulation supplemented with additional sources of carbon, nitrogen, and vitamin B12 at different levels and varying the agitation intensity according to a Plackett-Burman experimental design. Only the addition of tryptone positively influenced the production of this bacteriocin. The results allowed us to identify a supplemented whey formulation, comprising 150 g/L of whey total solids plus 10 g/L of tryptone and soybean extract, whose fermentation by Lb. plantarum ST16Pa in shake flasks under agitation at 150 rpm led to a cell-free supernatant with an antimicrobial activity against Listeria innocua 6a CLIST 2865 (inhibition zone of 13.23 mm) close to that previously obtained in de Man, Rogosa and Sharpe medium by other authors. These results are significant considering that the same strain cultured in cheese whey did not previously display any antimicrobial activity.

Investigation of the use of whey powder and buttermilk powder instead of skim milk powder in yogurt production.

The aim of this study was to determine some physical, chemical, microbiological and organoleptic properties of set-type yogurts made with six different skim milk powder (SMP), whey powder (WP) and buttermilk powder (BMP) during a 21-day period. Samples were taken from yogurts on day 1, 7, 14 and 21. Analyses were carried out on the total solids, fat, non-fat solids, protein, ash, viscosity, syneresis, pH, titratable acidity values. The counts of Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and yeasts-molds were enumerated. Also, sensory evaluations were performed at the same times. The substitution effect of WP and BMP for SMP on ash, viscosity, syneresis and titratable acidity values of yogurts were found to be significant (p < 0.05), while total solids, non-fat solids, protein contents, pH value and S. thermophilus, L. bulgaricus and yeasts-molds counts were not statistically significant. The effect of storage period on protein, ash, viscosity, and titratable acidity values, and L. bulgaricus and yeasts-mold counts was found to be significant (p < 0.05) statistically. However, it was observed that the changes of total solids, fat, non-fat solids, syneresis, pH values, and S. thermophilus counts were insignificant during the storage period. The sensory evaluations showed that sample D was most preferred by panelists.

Effects of dry whey powder and calcium butyrate supplementation of corn/soybean-based diets on productive performance, duodenal histological integrity, and Campylobacter colonization in broilers.

BACKGROUND: Campylobacter is the main cause of gastroenteritis in humans in industrialized countries, and poultry is its principal reservoir and source of human infections. Dietary supplementation of broiler feed with additives could improve productive performance and elicit health benefits that might reduce Campylobacter contamination during primary production. The aim of this study was to assess the effect of dietary supplementation with whey (a prebiotic) and calcium butyrate (a salt of a short-chain fatty acid) on productive traits, duodenal histological integrity, and Campylobacter colonization and dissemination in broiler chickens during the 42-day rearing period. RESULTS: Six hundred one-day-old Ross-308 chickens were placed into 20 ground pens and assigned to one of 4 corn/soybean-based dietary treatments (5 replicates of 30 chicks per treatment) following a randomized complete block design: 1) basal diet with no supplementation as the control, 2) diet supplemented with 6% dry whey powder, 3) diet containing 0.1% coated calcium butyrate, and 4) diet containing 6% whey and 0.1% calcium butyrate. At age 15 days, 6 chickens per pen were experimentally inoculated with Campylobacter jejuni. The results showed that supplementation of the corn/soybean-based diet with 6% whey alone or, preferably, in combination with 0.1% coated calcium butyrate improved growth and feed efficiency, had a beneficial effect on duodenal villus integrity, and decreased mortality. These favourable effects were particularly significant during the starter period. Six days after oral challenge, Campylobacter was widespread in the flock, and the birds remained positive until the end of the rearing period. Although Campylobacter was not isolated from environmental samples, it was detected by real-time polymerase chain reaction (PCR) in dust, air filters, and drinkers while birds shed culturable C. jejuni cells. No differences (p > 0.050) in colonization or shedding levels that could be attributed to the diet were observed during the assay. CONCLUSIONS: Beneficial effects on performance and intestinal health were observed, particularly during the starter period, when chickens were fed a diet supplemented with both whey and coated calcium butyrate. However, none of the tested diets provided the chicks any differential degree of protection against Campylobacter infection.

The effect of acidification of liquid whey protein concentrate on the flavor of spray-dried powder.

Off-flavors in whey protein negatively influence consumer acceptance of whey protein ingredient applications. Clear acidic beverages are a common application of whey protein, and recent studies have demonstrated that beverage processing steps, including acidification, enhance off-flavor production from whey protein. The objective of this study was to determine the effect of preacidification of liquid ultrafiltered whey protein concentrate (WPC) before spray drying on flavor of dried WPC. Two experiments were performed to achieve the objective. In both experiments, Cheddar cheese whey was manufactured, fat-separated, pasteurized, bleached (250 mg/kg of hydrogen peroxide), and ultrafiltered (UF) to obtain liquid WPC that was 13% solids (wt/wt) and 80% protein on a solids basis. In experiment 1, the liquid retentate was then acidified using a blend of phosphoric and citric acids to the following pH values: no acidification (control; pH 6.5), pH 5.5, or pH 3.5. The UF permeate was used to normalize the protein concentration of each treatment. The retentates were then spray dried. In experiment 2, 150 µg/kg of deuterated hexanal (D12-hexanal) was added to each treatment, followed by acidification and spray drying. Both experiments were replicated 3 times. Flavor properties of the spray-dried WPC were evaluated by sensory and instrumental analyses in experiment 1 and by instrumental analysis in experiment 2. Preacidification to pH 3.5 resulted in decreased cardboard flavor and aroma intensities and an increase in soapy flavor, with decreased concentrations of hexanal, heptanal, nonanal, decanal, dimethyl disulfide, and dimethyl trisulfide compared with spray drying at pH 6.5 or 5.5. Adjustment to pH 5.5 before spray drying increased cabbage flavor and increased concentrations of nonanal at evaluation pH values of 3.5 and 5.5 and dimethyl trisulfide at all evaluation pH values. In general, the flavor effects of preacidification were consistent regardless of the pH to which the solutions were adjusted after spray drying. Preacidification to pH 3.5 increased recovery of D12-hexanal in liquid WPC and decreased recovery of D12-hexanal in the resulting powder when evaluated at pH 6.5 or 5.5. These results demonstrate that acidification of liquid WPC80 to pH 3.5 before spray drying decreases off-flavors in spray-dried WPC and suggest that the mechanism for off-flavor reduction is the decreased protein interactions with volatile compounds at low pH in liquid WPC or the increased interactions between protein and volatile compounds in the resulting powder.

Valorization of Cheese Whey Powder by Two-Step Fermentation for Gluconic Acid and Ethanol Preparation.

Whey from cheesemaking is an environmental contaminant with a high biochemical oxygen demand (BOD), containing an abundance of lactose. Hence, it has the potential to be utilized in the manufacturing of bio-based chemicals that have increased value. A designed sequential fermentation approach was employed in this research to convert enzymatic hydrolysate of cheese whey (primarily consists of glucose and galactose) into gluconic acid and bio-ethanol. This conversion was achieved by utilizing Gluconobacter oxydans and Saccharomyces cerevisiae. Glucose in the enzyme hydrolysate will undergo preferential oxidation to gluconic acid as a result of the glucose effect from Gluconobacter oxydans. Subsequently, Saccharomyces cerevisiae will utilize the remaining galactose exclusively for ethanol fermentation, while the gluconic acid in the fermentation broth will be retained. As a result, approximately 290 g gluconic acid and 100 g ethanol could be produced from 1 kg of cheese whey powder. Simultaneously, it was feasible to collect a total of 140 g of blended protein, encompassing cheese whey protein and bacterial protein. Two-step fermentation has proven to be an effective method for utilizing cheese whey in a sustainable manner.

Efficient synthesis of 5-hydroxytryptophan in Escherichia coli by bifunctional utilization of whey powder as a substrate for cell growth and inducer production.

5-Hydroxytryptophan (5-HTP), a precursor of the neurotransmitter serotonin in mammals, has demonstrated efficacy in treating various diseases such as depression, fibromyalgia and obesity. However, conventional biosynthesis methods of 5-HTP are limited by low yield and high reagent and process costs. In this study, the strain C1T7-S337A/F318Y with optimized promoter distribution was obtained, and the 5-HTP yield was 60.30 % higher than that of the initial strain. An efficient fermentation process for 5-HTP synthesis was developed using strain C1T7-S337A/F318Y with whey powder as a substrate for cell growth and inducer production. Shake flask fermentation experiments yielded 1.302 g/L 5-HTP from 2.0 g/L L-tryptophan (L-Trp), surpassing the whole-cell biocatalysis by 42.86 %. Scale-up to a 5 L fermenter further increased the yield to 1.649 g/L. This fermentation strategy substantially slashed reagent cost by 95.39 %, providing a more economically viable and environmentally sustainable route for industrial biosynthesis of 5-HTP. Moreover, it contributes to the broader utilization of whey powder in various industries.

Characterization of a GH20 ß-N-Acetylhexosaminidase from Flavobacterium algicola Suitable to Synthesize Lacto-N-triose II.

ß-N-Acetylhexosaminidases have attracted much attention in the enzymatic synthesis of lacto-N-triose II (LNT2) as a backbone precursor of human milk oligosaccharides (HMOs). In this study, a novel glycoside hydrolase (GH) 20 family ß-N-acetylhexosaminidase, FlaNag2353, from Flavobacterium algicola was biochemically characterized and applied to synthesize LNT2. FlaNag2353 displayed optimal activity to p-nitrophenyl N-acetyl-ß-d-glucosaminide (pNP-GlcNAc) at 40 °C and pH 8.0. In addition to its excellent hydrolysis activity toward pNP-GlcNAc and chitooligosaccharides, FlaNag2353 showed trans-glycosylation activity. Under conditions of pH 9.0 and 55 °C for 2 h and utilizing 200 mM lactose and 10 mM pNP-GlcNAc, FlaNag2353 synthesized LNT2 with a conversion ratio of 4.15% calculated from pNP-GlcNAc. Moreover, when applied to LNT2 synthesis with 10 mM pNP-GlcNAc and 9.7% (w/v) industrial waste whey powder, FlaNag2353 achieved a conversion ratio of 2.39%. This study has significant implications for broadening the applications of GH20 ß-N-acetylhexosaminidases and promoting the high-value utilization of whey powder.

Production of D -tagatose, bioethanol, and microbial protein from the dairy industry by-product whey powder using an integrated bioprocess.

We designed and constructed a green and sustainable bioprocess to efficiently coproduce D -tagatose, bioethanol, and microbial protein from whey powder. First, a one-pot biosynthesis process involving lactose hydrolysis and D -galactose redox reactions for D -tagatose production was established in vitro via a three-enzyme cascade. Second, a nicotinamide adenine dinucleotide phosphate-dependent galactitol dehydrogenase mutant, D36A/I37R, based on the nicotinamide adenine dinucleotide-dependent polyol dehydrogenase from Paracoccus denitrificans was created through rational design and screening. Moreover, an NADPH recycling module was created in the oxidoreductive pathway, and the tagatose yield increased by 3.35-fold compared with that achieved through the pathway without the cofactor cycle. The reaction process was accelerated using an enzyme assembly with a glycine-serine linker, and the tagatose production rate was 9.28-fold higher than the initial yield. Finally, Saccharomyces cerevisiae was introduced into the reaction solution, and 266.5 g of D -tagatose, 162.6 g of bioethanol, and 215.4 g of dry yeast (including 38% protein) were obtained from 1 kg of whey powder (including 810 g lactose). This study provides a promising sustainable process for functional food (D -tagatose) production. Moreover, this process fully utilized whey powder, demonstrating good atom economy.

Freshwater microalgae Nannochloropsis limnetica for the production of ß-galactosidase from whey powder.

This study investigated the first-ever reported use of freshwater Nannochloropsis for the bioremediation of dairy processing side streams and co-generation of valuable products, such as ß-galactosidase enzyme. In this study, N. limnetica was found to grow rapidly on both autoclaved and non-autoclaved whey-powder media (referred to dairy processing by-product or DPBP) without the need of salinity adjustment or nutrient additions, achieving a biomass concentration of 1.05-1.36 g L-1 after 8 days. The species secreted extracellular ß-galactosidase (up to 40.84 ± 0.23 U L-1) in order to hydrolyse lactose in DPBP media into monosaccharides prior to absorption into biomass, demonstrating a mixotrophic pathway for lactose assimilation. The species was highly effective as a bioremediation agent, being able to remove > 80% of total nitrogen and phosphate in the DPBP medium within two days across all cultures. Population analysis using flow cytometry and multi-channel/multi-staining methods revealed that the culture grown on non-autoclaved medium contained a high initial bacterial load, comprising both contaminating bacteria in the medium and phycosphere bacteria associated with the microalgae. In both autoclaved and non-autoclaved DPBP media, Nannochloropsis cells were able to establish a stable microalgae-bacteria interaction, suppressing bacterial takeover and emerging as dominant population (53-80% of total cells) in the cultures. The extent of microalgal dominance, however, was less prominent in the non-autoclaved media. High initial bacterial loads in these cultures had mixed effects on microalgal performance, promoting ß-galactosidase synthesis on the one hand while competing for nutrients and retarding microalgal growth on the other. These results alluded to the need of effective pre-treatment step to manage bacterial population in microalgal cultures on DPBP. Overall, N. limnetica cultures displayed competitive ß-galactosidase productivity and propensity for efficient nutrient removal on DPBP medium, demonstrating their promising nature for use in the valorisation of dairy side streams.

Efficient production of d-tagatose via DNA scaffold mediated oxidoreductases assembly in vivo from whey powder.

Among the emerging sweeteners, d-tagatose occupies a significant niche due to its low calorific value, antidiabetic property and growth promoting effects on intestinal probiotics. Recently, the main approach for d-tagatose biosynthesis is l-arabinose isomerase-based isomerization reaction from galactose, which shows relatively low conversion rate because of unfavorable thermodynamic equilibria. Herein, oxidoreductases, d-xylose reductase and galactitol dehydrogenase, together with endogenous ß-galactosidase were employed to catalyze the biosynthesis of d-tagatose from lactose with a yield of 0.282 g/g in Escherichia coli. Then, a deactivated CRISPR-associated (Cas) proteins-based DNA scaffold system was developed, which were proved to be efficient for assembling the oxidoreductases in vivo and got a 1.44-folds increase in d-tagatose titer and yield. Further, by employing d-xylose reductase with higher galactose affinity and activity, as well as overexpressing pntAB genes, the d-tagatose yield from lactose (0.484 g/g) increased to 92.0 % of the theoretical value, 1.72-times as that of original strain. Finally, whey powder, a lactose-rich food by-product, was bifunctionally utilized as an inducer and substrate. In the 5 L bioreactor, d-tagatose titer reached 32.3 g/L with little galactose detected, and the yield from lactose approached 0.402 g/g, which was the highest from waste biomass in the literature. The strategies used here might provide new insights into the biosynthesis of d-tagatose in future.

Use of microencapsulated starter cultures by spray drying in coffee under self-induced anaerobiosis fermentation (SIAF).

Using starter culture in liquid form is not economically viable in the coffee fermentation process. This work aimed to compare the fermentative performances of fresh and microencapsulated yeasts in coffee under self-induced anaerobic fermentation (SIAF). The inoculum permanence was monitored, and sugars, alcohols, acids, and volatile compounds were analyzed by chromatography. In addition, sensory analysis was performed on roasted beans. After 180 h of fermentation in the natural process, microencapsulated Torulaspora delbrueckii (MT) (7.97 × 107 cells/g) showed a higher population thanfresh Torulaspora delbrueckii (FT) (1.76 × 107 cells/g). The same acids and volatile compounds were detected in coffees with fresh and microencapsulated yeast. However, the yeast state influenced the concentration of the compounds. In pulped coffee, the coffee inoculated withmicroencapsulated Saccharomyces cerevisiae (MS) obtained the highest concentration of alcohols, esters, pyrazines, and others compared with fresh Saccharomyces cerevisiae (FS), with an increase of up to 47%. Furthermore, the coffee inoculated with MT obtained the highest concentration in almost all chemical classes in both processes compared with FT. These differences ranged up to 55%. Regarding sensory analysis, coffees inoculated with MS showed dominant notes of fruity, caramel, and nuts in the natural process. Otherwise, in pulped process, coffees inoculated with MT showed caramel, honey, and nuts. Therefore, the microencapsulated yeasts were metabolically active and may be considered with commercial potential. Considering the parameters analyzed, the most suitable yeast for natural and pulped processing would be MS and MT, respectively.

Biocatalytic conversion of a lactose-rich dairy waste into D-tagatose, D-arabitol and galactitol using sequential whole cell and fermentation technologies.

Dairy industry waste has been explored as a cheap and attractive raw material to produce various commercially important rare sugars. In this study, a lactose-rich dairy byproduct, namely cheese whey powder (CWP), was microbially converted into three low caloric sweeteners using whole-cell and fermentation technologies. Firstly, the simultaneous lactose hydrolysis and isomerization of lactose-derived D-galactose into D-tagatose was performed by an engineered Escherichia coli strain co-expressing ß-galactosidase and L-arabinose isomerase, which eventually produced 68.35 g/L D-tagatose during sequential feeding of CWP. Subsequently, the mixed syrup containing lactose-derived D-glucose and residual D-galactose was subjected to fermentation by Metschnikowia pulcherrima E1, which produced 60.12 g/L D-arabitol and 28.26 g/L galactitol. The net titer of the three rare sugars was 156.73 g/L from 300 g/L lactose (equivalent to 428.57 g/L CWP), which was equivalent to 1.12 mol product/mol lactose and 52.24% conversion efficiency in terms of lactose.

Microencapsulation of epiphytic coffee yeasts by spray drying using different wall materials: Implementation in coffee medium.

The storage of microorganisms in liquid form is the main drawback of commercializing epiphytic coffee yeasts. This work aimed to evaluate the fermentative performance of microencapsulated yeasts by spray drying in a coffee peel and pulp media (CPM). The yeasts, Saccharomyces cerevisiae CCMA 0543, Torulaspora delbrueckii CCMA 0684, and Meyerozyma caribbica CCMA 1738, were microencapsulated using maltodextrin DE10 (MD), high maltose (MA), and whey powder (WP) as wall materials. A Central Composite Rotational Design (CCRD) was used to investigate the effect of operating parameters on the microcapsules' cell viability, drying yield, and water activity. Yeasts reached cell viability and drying yields above 90 and 50 %, respectively. WP maintained the cell viability of the three yeasts over 90 days of storage at room temperature (25 °C) and was selected as a wall material for the three yeasts. M. caribbica showed to be more sensitive to spray drying and less resistant to storage. Some differences were found in the fermentation of the CPM medium, but the microencapsulated yeasts maintained their biotechnological characteristics. Therefore, the microencapsulation of epiphytic coffee yeasts by spray drying was promising to be used in the coffee fermentation process.

Challenges in dried whey powder production: Quality problems.

Whey is a high nutritional value by-product of the dairy industry. It is generally produced in large quantities and its disposal as wastewater poses environmental risks. For this reason, whey streams are used for the production of value-added products such as dried whey powders. However, there are several challenges related to whey processing that lead to low powder yield and quality, especially caking. These challenges can be addressed by optimization of product formulation and processing parameters. In this review, we discuss the effects of dried whey protein powder production stages and process parameters on the quality of the final powder product. The initial composition of whey used for dried whey powder production affects the final quality of the product. Generally, a high mineral and/or lactic acid content is not desirable since these constituents cause lactose-containing whey particles to adhere to the drying equipment surfaces, thereby reducing the powder yield. An effective lactose pre-crystallization is essential since high amorphous lactose content increases the stickiness of the dried-whey powder particles and induces caking during storage. Therefore, whey should undergo filtration and lactose pre-crystallization before spray drying. Studies show that it is possible to retard caking and improve the quality attributes of dried whey powders by optimizing the product formulation and processing operations.

Biochemical, dielectric and surface characteristics of freeze-dried bovine colostrum whey powder.

Colostrum samples of recently registered cow breed "Himachali Pahari" were assorted from high altitude zone (901-2200 m). Prepared bovine colostrum whey powder (BCWP) was analysed for chemical composition, amino acids, minerals, surface morphology (SEM-EDS), FTIR and dielectric properties. Results showed that freeze-dried BCWP contained a considerable amount of nutritional parameters viz IgG (18.55 g/100 g), protein (71.72 g/100 g) and total amino acids (69.64 g/100 g). Additionally, the concentration of essential minerals was found to be adequate, and there was no presence of heavy metals. The BCWP exhibits good dielectric properties (resistance ∼57 M-Ω). SEM-EDS showed the broken up-wards layer structure with the uniform distribution of minerals on the surface. The FTIR spectra confirmed the presence of a higher proportion of ß-sheets and ß-turn structures in BCWP. Thus, on account of good functional and nutritive properties, BCWP could be foreseen as the future of functional food.

Bifunctional utilization of whey powder as a substrate and inducer for ß-farnesene production in an engineered Escherichia coli.

ß-Farnesene can replace petroleum products as specialty fuel to solve the global fuel energy crisis, but its production by Escherichia coli (E.coli) using glucose and isopropyl ß-D-1-thiogalactopyranoside (IPTG) is costly. Hence, we developed a new strategy to produce ß-farnesene by engineered E.coli strain F13 with bifunctional utilization of whey powder. The utilization of whey powder as a substrate ensured the growth of the strain F13, while whey powder could also replace IPTG to induce the production of ß-farnesene. In shake flasks, ß-farnesene production reached 2.41 g/L by the bifunctional utilization of whey powder as a substrate and inducer, 65.1% higher than that with IPTG and glucose. In the 7 L bioreactor, ß-farnesene production reached 4.74 g/L using whey powder, which was 197% of that in shake flasks. Therefore, this new strategy might be an attractive route to broaden the applications of whey powder and achieve the economical production of ß-farnesene.