Enzymatic Hydrolysis Of Potato Protein And The Application Of Hydrolysate On Weaned Piglets

The present study was conducted to establish the optimal enzymolysis parameters for potato protein hydrolysis in vitro and evaluate the effects of the hydrolysate on performance of weaned piglets.Experiment 1.Optimal enzymolysis parameters for potato protein hydrolysis in vitro and Preparation of Gin-containing PeptideThe analytic grade of Pepsin and Trypsin were used to prepare Gln-containing peptides from potato protein. A temperature gradient(40 45 50 55℃respectively) trial was conducted first to determine the optimal temperature for each enzymatic reaction.The hydrolytical conditions were then optimized via L~9(3~4) orthogonal experiment design(three levels of initial pH value,enzyme concentration and reaction time,respectively);Finally,the combination hydrolysis of both pepsin and trypsin was performed at a pepsin dosage of 2000U/g and trypsin dosage of 1/4,1/2 and 3/4 of its optimal dose respectively.Results showed that the optimal pH and temperature for pepsin and trypsin were 1.8 and 9.0,50℃and 45℃,respectively.The ideal concentrations of the two enzymes were 5000U/g and 500U/g respectively.Both had the same optimal reaction time.Under the optimized condition of combination hydrolysis,the end hydrolysate contains as much as 5.85%of Gin with a yield rate of 86.39%,DH is 9.86%,TCA-NSI is 49.28%.Experiment 2.The effects of hydrolytic products on performance of weaned pigletsA total of 28,crossbred weanling pigs(initial body weight 7.38±0.66kg) were assigned to one of four treatments to investigate the influences of hydrolytic products on pig performance.Pigs of four treatments were fed ad.libitum corn-soybean-meal control diet,or diets substituted 5%soybean meal with equal potato protein(PP), hydrolytic potato protein(HPP),or spray-dried porcine plasma protein(SDPP), respectively.All pigs were housed in an environmentally controlled modular building and received a 14-d trial.On d 8 of the trial,blood samples were collected by venipuncture.At the end of the trial,6 piglets from each treatment were slaughtered and the tissues of small intestine were smapled to determine the villus morphology. The mucosa was collected for analysis of protein,Gin and nucleic acid content. Resuts demonstrated that the treatment of HPP significantly improved the performance(ADG,ADFI and F/G) of piglets during the 1st week;However,the SDPP substitution improved the performance throughout the trial;The morphological parameters of villous height,crypts depth of small intestine were greater in HPP than other groups(P＜0.01 or P＜0.05).Both HPP and SDPP treatments significantly promoted the mucosa DNA synthesis.In addtioin,the mucosa protein and SIgA content,the serum globulin,Glu and SUN were both increased in HPP group(P＜0.05). These results suggested that the HPP may be one of the attractive protein sources for weanling piglets.