| Pea(Pisum sativum Linn)is an important resource of pulses,which is mainly distributed in central,northeastern and other regions in China.Pea is rich in protein,starch,dietary fiber,B vitamins,various trace elements and polyphenols.The Compendium of Materia Medica records:"the flavor of the pea is sweet and pea is mild-natured,spleen-invigorating and stomach meridian-improving;pea is also beneficial in replenishing qi,stoping diarrhea,regulating Ying Wei,promoting diuresis,eliminating carbuncle swelling,and detoxifying Ru Shi poisoning".In recent years,given the abundant nutrition and low price of pea,more and more researchers and enterprises have been devoted to utilizing pea in developing staple foods and leisure foods.However,because of the lack of gluten protein,bad taste,poor taste,and rapid starch return,the pea has severe constraints on its application in staple food.In this work,to illuminate the processing suitability of pea starch,both the macro and micronutrients in pea have been firstly determined;then the physicochemical properties of pea starch was analyzed;and the effect of ultra-high pressure processing technology on the features of pea starch was also observed.These obtained results are very important to solving the bottleneck problem in how to taking advantage of pea in producing staple foods.Furthermore,the fine dried pea noodles were developed,which meet the requirements of the relevant state regulations and accompany with both high nutritive value and good taste.Finally,the effect of processing methods including soaking,germination,hot and humid cooking and extrusion on the blood glucose homeostasis in mice were also studied.This work is very significant to ultilizing pea in development of special diets for high blood glucose group.The main results are as follows:(1)The composition is an important factor affecting the gel process and texture characteristics of pea starch.According to the results of macros and micronutrient characteristic analysis,the carbohydrate content of pea was 62.40%,of which the starch content was 53.35%,the amylose was 12.52%and the resistant starch content was 7.07%.The crude protein content was 23.30%,which was much higher than that of wheat,rice and other grains,and the high content of the restrictive amino acid lysine and threonine was 1.51%and 0.74%respectively.The pea also contains high mineral elements,with 2.64%ash and 0.29 ppm of the selenium content,In addition,the pea contains a variety of polyphenols and the total phenol content is 2.54%.(2)Based on the analysis of physicochemical properties of pea starch,the content of amylose in pea starch was up to 45.64%,and the retrogradation starch content was 46.12%.This results indicated that pea starch was an important raw material for resistant starch.According to the observation of scanning electron microscopy,pea starch has a smooth appearance and is mostly in the shape of the kidney.Pea starch exhibited lower solubility at 30 ? and 50 ?;however,the solubility increases significantly when the temperature is more than 70 ? and the solubility was more reach 13.6%at 90 ?.The swelling force of pea starch increased significantly(p<0.05)with temperature.Compared with othe pulses,pea starch also has good light transmittance.And for pea starch,the attenuation value,peak viscosity,low viscosity,final viscosity,setback and peak time and pasting temperature is 2660 Pa新?2048 Pa新?612 Pa新?3232 Pa新?1185 Pa新?5.44 minand69 ?,respectively.According to the the results of thermodynamic properties,there are no significant difference in ?H between pea starch and other pulses.For pea starch,the initial pasting temperature was 59.6 ?,which is close to the rice starch,but much higher than that of wheat starch.(3)The physical and chemical properties and in vitro digestibility of pea starch were significantly affected by high hydrostatic pressure treatment(p<0.05).Under the ultrahigh pressure treatment of 600 MPa,the crystalline form of pea starch changed from type C to type B,and the morphological structure of starch granules was completely destroyed.Compared with untreated and 150-450mpa treated pea starch,the starch treated with 600 MPa was more granular and the peak viscosity,minimum viscosity,attenuation value,final viscosity and return value were lower.Pea starch under 30-70 ? show higher hydration performance,but under the 90 ? the starch show low hydration performance.The gelatinization temperature and the pasting enthalpy of pea starch decreased with the increase of pressure.In addition,the in vitro hydrolysis of the treated starch was lower than the original one,and the content of starch RDS was decreased,and the content of resistant starch RS increased.However,the structure of starch under 600 MPa pressure was instantaneous,and the effect of pressure time on the structure and physical properties of starch granules was not significant.(4)During the processes of development of the fine dried pea noodles,it was found that PM-SC-Y and PM-SF-Y made by needle grinding and RM-R-Y produced by roller mill were suitable for processing pea noodles.The optimum amount of unmodified pea meal was only 20%.The optimum processing conditions for producing pea noodles are:water content is 32%,the water temperature 25 ?,the dough curing time is 45 min,the curing temperature of is 30 ?,the rolling time is 7 times.The pregelatinized treatment had a significant(p<0.05)effect on the quality of the pea noodles,and the quality of the pea noodles was the best when the amount of pregelatinized powder was 30%.The study on the effect of storage conditions on the quality of pea noodles has found that the storage temperature is the critical to the storage quality of the pea noodles,and the higher temperature is,the faster the quality deterioration is.The influence of infrared treatment on the storage quality of the pea noodles is not significant.The change of moisture content is not significant to the storage quality of the pea noodles,too.(5)In this work,both the normal and diabetic mice were employed to postprandial blood glucose evaluation.The results indicated that the glycemic index in pea group was significantly(p<0.05)lower than that of wheat flour group.The glycemic index of pea meal was improved significantly(p<0.05),and the glycemic index was significantly(p<0.05)increased with the increase of soaking time.The process of germination was significant(p<0.05)to improve the glycemic index of pea meal,and the glycemic index of pea was also significantly(p<0.05)increased with the increase of germination time.At the same condition,the glycemic index of pea meal was significantly(p<0.05)improved by cooking,and the glycemic index of pea was significantly increased with the increase of cooking time(p<0.05).The glycemic index of pea meal was significantly(p<0.05)improved by extrusion processing,but the change of glycemic index of pea was not obvious(p<0.05)with the increase of extrusion temperature.(6)In this work,how the pea meal influence on the serum biochemical indexes in diabetes mice was further observed.The results showed that after 21 d feeding,the weight of mice in wheat flour group increased,however,the peas group reduced.It is noteworthy that that the weight loss of mice in the group of soaking treatment 3 h was much more than other pea groups Compared with the 7 d feeding,there was significant(p<0.05)difference in blood glucose levels after 14 d feeding.The blood glucose level in groups of pea powder soaked in 3 h and sprouted 24 h was generally lower than that of other processing methods.And when diabetic mice administrated with pea starch,the diabetic symptoms were relieved:the blood lipid metabolism resumed normal,and the concentrations of TC and triglyceride were at a low level.The results showed that pea flour had the effect of lowering blood lipid in diabetic mice.In addition,all different treatment methods for pea can effectively improve the serum total antioxidant capacity and reduce insulin ecretion in diabetic mice. |
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