Kinetic study of alkaline protease 894 for the hydrolysis of the pearl oyster Pinctada martensii

A new enzyme (alkaline protease 894) obtained from the marine extremophile Flavobacterium yellowsea (YS-80-122) has exhibited strong substrate-binding and catalytic activity, even at low temperature, but the characteristics of the hydrolysis with this enzyme are still unclear. The pearl oyster Pinctada martensii was used in this study as the raw material to illustrate the kinetic properties of protease 894. After investigating the intrinsic relationship between the degree of hydrolysis and several factors, including initial reaction pH, temperature, substrate concentration, enzyme concentration, and hydrolysis time, the kinetics model was established. This study showed that the optimal conditions for the enzymatic hydrolysis were an initial reaction pH of 5.0, temperature of 30°C, substrate concentration of 10% (w/v), enzyme concentration of 2 500 U/g, and hydrolysis time of 160 min. The kinetic characteristics of the protease for the hydrolysis of P. martensii were obtained. The inactivation constant was found to be 15.16/min, and the average relative error between the derived kinetics model and the actual measurement was only 3.04%, which indicated a high degree of fitness. Therefore, this study provides a basis for the investigation of the concrete kinetic characteristics of the new protease, which has potential applications in the food industry.

Study on the Technologic Optimization for Hydrolysis of Silver carp By-products

The hydrolysis process for Silver carp by-products was studied. Protein hydrolysate was prepared with proteolytic enzyme, Alcalase. Hydrolysis conditions were optimized by the regression model of three factors five levels quadratic rotation perpendicular regressive design. The optimum hydrolysis conditions of hydrolyzing the protein of Silver carp by-products were determined to be concentration of enzyme (E/S) 3.33%, pH 8.54, hydrolyzing temperature 58 ℃, reaction time 90 min, concentration of substrate 8%. Nitrogen recovery was more than 75%.

Optimization of the ultrasonic-microwave assisted enzymatic hydrolysis of freshwater mussel meat

In the present study,the Ultrasonic-Microwave(US-MW)technique was applied for assisting enzymatic hydrolysis of freshwater mussel meat.The operating parameters of enzymatic hydrolysis were investigated and the properties and qualities of the freshwater mussel hydrolysates were also analyzed.The considerable optimum conditions for enzymatic hydrolysis of mussel meat were ratio of liquid to material of 10.36:1,power of 360.52 W,processing time of 6.91 min,enzymolysis time of 4 h.Under these conditions,a degree of hydrolysis(DH)of 48.40% was obtained.The hydrolysates produced under optimum conditions,were characterized in terms of electrophoretic profile,amino acid composition and infrared spectrum analysis.SDS-PAGE profiles of the hydrolysates revealed that several protein bands were cleaved and several light myosin chains(25 kDa and 15 kDa,respectively)and peptides of molecular weight lower than 6.5 kDa were identified.The infrared spectrum absorption peak of amide band A and band III shifted after US-MW pre-treatment,which indicated that the N-H(hydrogen bonding)stretching vibration and triple helix structure of samples were affected.The essential amino acids in hydrolysates with or without US-MW pre-treatment were 36.62 mg/100 g and 33.40 mg/100 g.It was proved that US-MW assisted enzymatic hydrolysis is an effective technology to utilize freshwater mussel meat.

Optimization of hydrolysis conditions for the production of protein hydrolysates from fish wastes using response surface methodology

The recycling of waste from food processing is an important industrial procedure for obtaining protein sources with high added value.In this study,trout(Onchorynchus mykiss),anchovy(Engraulis encrasicolus),and whiting(Merlangius merlangus)wastes were hydrolyzed.The hydrolyzation procedure was investigated under the optimum predicted conditions defined by time,temperature,and enzyme ratio(E/S)using alkaline protease(pH 8),Protamex(pH 7),and Flavourzyme(pH 7).The hydrolysis conditions that showed the best degree of hydrolysis(DH%)were optimized using response surface methodology(RSM)with the central composite design(CCD)and Box-Behnken design(BBD)models.The effects of three independent variables,temperature(40-60℃),time(1-8 h),and enzyme concentrations(1-2%),were examined for model optimization.It was determined that the DH%varies between 50.92%and 74.30% according to the type of fish waste and enzyme.The highest degree of hydrolysis was observed from trout waste(74.30%)and the lowest degree from whiting waste(50.92%)with Flavourenzyme.From this study,it has been shown that different degrees of hydrolysis and protein recovery can be obtained,depending on fish species,waste composition,enzyme type,and hydrolysis method.

Lima Bean(Phaseolus lunatus)Protein Hydrolysates with ACE-I Inhibitory Activity

Several protein sources can be used to produce bioactive peptides with angiotensin I-converting enzyme (ACE) inhibittory activity. Protein concentrates from ungerminated and germinated lima bean Phaseolus lunatus seed flours were hydrolyzed with Alcalase 2.4 L or pepsin-pancreatin sequential hydrolysis, and ACE inhibitory activity measured in the different hydrolysis treatments. Protein hydrolysate production was analyzed with a 23 factorial design with four replicates of the central treatment. Evaluated factors were protein concentrate source (ungerminated seeds, PC1;germinated seeds, PC2), enzyme/substrate ratio E/S (1/50 or 1/10) and hydrolysis time (0.5 or 2.0 h for Alcalase;1 or 3 h for pepsin-pancreatin). Degree of hydrolysis (DH) was high for the Alcalase hydrolysates (24.12% 58.94%), but the pepsin-pancreatin hydrolysates exhibited the highest ACE inhibitory activity (IC50 = 0.250 0.692 mg/mL). Under the tested conditions, the hydrolysates with the highest ACE inhibitory activity were produced with sequential pepsin-pancreatin using either PC1 at 1 h hydrolysis time and a 1/10 E/S ratio or PC2 at 1 h hydrolysis time and a 1/50 E/S ratio. Lima bean protein hydrolysates prepared with Alcalase or pepsin-pancreatin are a potential ingredient in the production of physiologically functional foods with antihypertensive activity.