Showing papers by "Saroat Rawdkuen published in 2009"

Biochemical and functional properties of proteins from red kidney, navy and adzuki beans

Abstract: Chemical composition and functional properties of proteins extracted from adzuki, navy and red kidney beans were investigated. Protein contents were 17.33, 18.15 and 19.91% for red kidney, navy and adzuki beans, respectively. Red kidney bean exhibited the highest carbohydrates content, while the highest fat, ash and crude fibre content was found in navy bean. The highest trypsin inhibitory activity was found in adzuki bean. Globulin polypeptides (molecular weight ranges 45-55 kDa) were the major polypeptides in both whole protein and protein isolate. Protein isolate from all seeds contained at least one major glycopeptide, while more than two major glycopeptides were observed in the whole proteins. The minimum protein solubility of isolated proteins from all seeds was at around pH of 4-5. High foamability and foam stability were obtained in red kidney and navy beans when compared with those of adzuki bean. The highest oil absorption was found in adzuki bean, while no significant differences for water absorption between adzuki and red kidney beans was observed (p>0.05). Red kidney bean showed lower emulsifying activity as well as stability when compared with the other two beans.

Partitioning of bromelain from pineapple peel (Nang Lae cultv.) by aqueous two phase system.

Abstract: Pineapple peel is a potential source for the extraction of beneficial bioactive compounds due to the large amount of waste after processing. The extraction of bromelain from pineapple peel by using aqueous two-phase system (ATPs) and its application in muscle models were investigated. Bromelain predominantly partitions to the polyethylene glycol (PEG) rich top phase. The highest enzyme activity and recovery were presented in the top phase of 15% PEG-3000-20%MgSO4. Protein pattern and activity staining showed the molecular weight (MW) of bromelain was 29 kDa. The extracted bromelain showed the highest activity when incubated with buffer pH 9.0. Its activity decreased by 50% after 5 min incubation at 90°C and dropped drastically after 10 min incubation. Its activity also decreased continuously with increasing of NaCl concentration. Crude bromelain extract was applied to the muscles of beef, giant catfish and squid at the levels 0.05-1.0 grams per two grams of muscle. Higher muscle protein breakdown was observed to occur more in the beef and the giant catfish muscles than that of the squid sample. The myosin heavy chain (MHC) of beef and giant catfish muscles was extensively degraded into degradation proteins with lower MW.

Extraction of trypsin inhibitor from three legume seeds of the Royal Project Foundation.

Abstract: Trypsin inhibitor was isolated from navy bean (Phaseoulus vulgaris), red kidney bean (Phaseoulus vulgaris L) and adzuki bean (Vigna angularis) from the Royal Project Foundation, Thailand. Extraction of navy bean and red kidney bean with 0.02 M NaOH showed the highest recovery of trypsin inhibitor, while water was the best extractant for adzuki bean. The extraction time significantly affected the trypsin inhibitor recovery (p<0.05). Two hours of extraction gave the highest yield of trypsin inhibitor from three legumes. The trypsin inhibitors were estimated to have molecular weight of 132, 118 and 13 kDa under non-reducing conditions for navy bean, red kidney bean and adzuki bean, respectively. The inhibitory activities of the inhibitor from these legumes were lost when they were treated with β-mercaptoethanol, indicating the subunit of polypeptide in its composition.