Spent brewer's yeast (Saccharomyces cerevisiae) is a rich source of protein, vitamins and widely used as a raw material for production of food supplements. The autolysis and enzymatic treatment of spent brewer's yeast using Pancreatin (2.5%) and Flavourzyme (2.5%) were performed at 45 o C and 50 o C, respectively. The autolysis and hydrolysis processes were evaluated by determining a soluble solids, soluble protein concentration and α-amino nitrogen content in a reaction mixture. The yield of pancreatic digest and α-amino nitrogen content was high in comparison with autolysis and Flavourzyme treatment. The total solids recovery in dry Yeast hydrolysate was about 50%, a protein and α-amino nitrogen content was 55.9 and 4.8%, respectively. These results show the possibility of utilizing the spent brewer's yeast as hydrolysate using hydrolytic enzymes and use it as a food supplement after biological experiments.

Antioxidant activity of pancreatic hydrolysates of casein, spent brewer's yeast, bovine liver and tendon was evaluated in comparison to unhydrolised substrates by ABTS assay. In the result of enzymic treatment ABTS cation radical scavenging activity of spent brewer's yeast, bovine liver and bovine tendon was increased in 4.8, 3.3, and 2.3 times respectively, except casein. The IC 50 values of ABTS cation radical scavenging for casein and it's hydrolysate were similar. The IC 50 values of DPPH radical scavenging activity for pancreatic hydrolysates of casein, spent brewer's yeast, bovine liver and tendon were 1.8±0.1 mg/ml, 1.3±0.1 mg/ml, 1.7±0.1 mg/ml, and 6.2±0.1 mg/ml respectively. Above mentioned hydrolysates of various origin were produced at the same conditions (temperature 50 o C, pH 7.5-8.9, duration 5 hours) using fresh bovine pancreatic tissue as an enzyme source. The extent of hydrolysis expressed as AN/TN (amino nitrogen/ total nitrogen) for hydrolysates had values from 0.36±0.02 to 0.46±0.04.

The aim of this study was to determine the effect of spent brewer's yeast hydrolysate on the stabilization of lecithincontaining oil-in-water emulsion. The emulsion was prepared using a 1: 9 oil-to-water ratio with 8% lecithin and homogenized for30 min at 10,000 and 13,000 rpm. The brewer's yeast hydrolysate was added to the lecithin-based oil-in-water emulsion by 0.5%, 1.5%, and 3%, respectively. The oil droplet diameter and creaming index of emulsions were determined by comparison with the control. The stability of the emulsion containing 1.5% of brewer's yeast hydrolysate was 88.2%, and the proportion of oil droplets with a diameter of 1.5-3 μm reached 80%, which is an advantage over other options. The addition of brewer's yeast hydrolysate to the emulsion by 1.5% resulted in a 4.4-fold increase in the IC50 value of 2,2ʹ -azinobis- (3-ethyl-benzothiazolin-6-sulfonic acid) (ABTS) cationic radical inhibition. These results suggest that the use of 1.5% brewer's yeast hydrolysate to produce lecithin-based oil-in-water emulsion has a positive effect on emulsion stability and antioxidant activity, while increasing nutritional value. Пивоны дрожжийн гидролизат агуулсан усан суурьтай эмульсийн тогтворжилтын судалгаа Хураангуй: Энэхүү судалгааны ажилд пивоны дрожжийн гидролизатыг лецитин агуулсан усан суурьтай эмульсийн тогтворжилтод үзүүлэх нөлөөллийг тодорхойлох зорилтыг тавьсан. Эмульсийг бэлтгэхэд тос, усны харьцааг 1:9,лецитинийг 8%-иар авч 10000 ба 13000 эрг/мин хурдтайгаар нийт 30 мин гомогенжүүлэв. Лецитин агуулсан усан суурьтай эмульсийн найрлагад пивоны дрожжийн гидролизатыг 0.5%, 1.5%, 3%-иар нэмж, эмульс дэх тосны бөмбөлгийн диаметр, өтгөрөлтийн индексийг хяналтын эмульстэй харьцуулан тодорхойлов. Пивоны дрожжийн гидролизатыг 1.5%-иар агуулсан эмульсийн тогтворжилт 88.2% байсан ба 1.5-3 μм диаметртэй бөмбөлгийн эзлэх хувь 80%-д хүрсэн нь бусад хувилбараас давуу үзүүлэлт болно. Пивоны дрожжийн гидролизатыг эмульсийн найрлагад 1.5%-иар нэмэхэд 2,2ʹ -azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) (ABTS) катион радикал дарангуйлах IC50 утга 4.4 дахин нэмэгдэж байсан ба гидролизатын концентрацаас хамааран эмульсийн антиоксидант идэвх нэмэгдэж байсан. Эдгээр дүн лецитин агуулсан усан суурьтай эмульс гарган авахад пивоны дрожжийн гидролизатыг 1.5%-иар нэмж ашиглах нь тэжээллэг чанарыг нэмэгдүүлэхийн хамтаар эмульсийн тогтворжилт, антиоксидант идэвхэд эерэгээр нөлөөлж байгааг харуулж байна.  Түлхүүр үг: Гидролизат, эмульс, бөмбөлгийн хэмжээ, тогтворжилт, антиоксидант идэвх

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Silibum marianum (Milk thistle) contains high amount of phenolic compounds with antioxidant properties. The aim of this work was to evaluate the antioxidant activity of  phenolic compounds included in Milk thistle. The  antioxidant properties of the leaves and seeds of milk thistle were examined by determining its ability to scavenge the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. The results obtained from DPPH assay confirm that Milk thistle extracts have high antioxidative activity.DOI: http://doi.dx.org/10.5564/mjc.v15i0.323 Mongolian Journal of Chemistry 15 (41), 2014, p53-55