Study On Nutritional Components,in Vitro Digestive Characteristics Of Roasted Peanut And Processing Technology Of Roasting Peanut Yoghurt

Peanut,also named as groundnut,is a legume herb of the genus Rosaceae.It is known as “plant meat” and has high nutritional value.The main cooking methods of peanuts in China include boiling,roasting and frying.These thermal processing methods can change the flavor of peanuts and also affect the nutrients and digestion characteristics.The aim of this study was to investigate the comparative effects of different household cooking such as boiling,roasting,frying on the content of constitutional mainly include main nutrients and flavors such as carbohydrates,proteins,fats and amino acids and potential harmful such as acrylamide and furan components in peanuts.Compare the effects of different,processing methods on peanut nutrition,flavor and food safety.On this basis,the digestion characteristics of roasted peanuts and the changes of acrylamide,furan and other harmful substances were determined during in vitro digestion,and the processing suitability of roasted peanuts was discussed from the perspective of absorption and metabolism.Finally,the roasted peanuts are made into fermented yoghurt,and the fermentation process is optimized to promote the development of new healthy foods for roasting peanuts.The main researches and results of this thesis are as follows:1.By detecting the changes of main nutrients and flavor substances in boiled peanuts,roasted peanuts and fried peanuts,it was found that after thermal processing,the nutrients such as amino acids,reducing sugars and unsaturated fatty acids in peanuts decreased while the total saturated fatty acids has increased,and roasting and frying could significant affect it.It was also found that roasting and frying can also promote the formation of furan,HMF,acrylamide,CML,and CEL.In addition,GC-MS analysis found that raw peanuts and boiled peanuts contain a large amount of non-heterocyclic compounds,while roasted peanuts and fried peanuts contain a large number of heterocyclic compounds such as pyrazine and furan derivatives,of which pyrazines only present in roasted peanuts.2.The changes of peanut color and main Maillard reaction products under different roasting conditions were tested.The Maillard reaction products including acrylamide,HMF,CML and CEL under different roasting conditions were compared by multivariate analysis of variance.The results show that the main effects of heating time and heating temperature on acrylamide,HMF and CEL are significant,and there is an interaction between the two factors.For CML,only the heating temperature has a significant effect.Further more,I have investigated the effects of in vitro digestion on the main harmful compounds in raw peanuts and roasted peanuts.Compared with oral digestion and gastric digestion,intestinal digestion has the greatest effect on the harmful substances in peanuts.For example,pyrrolidine was detected after the intestine digestion in raw peanuts,acrylamide,CML and CEL in raw peanuts were also increased after digestion in the intestine.The α-dicarbonyl compounds in roasted peanuts were significantly increased after intestine digestion,especially for GO,MGO and 2,3-BD.The content of pyrrole,CML and CEL in roasted peanuts also increased significantly after intestine digestion.It can be seen that the in vitro digestion,especially the intestine digestion,has a greater influence on the α-dicarbonyl compound and the main Maillard reaction products,indicating that it can significantly increase the content of potential harmful substances in the peanut.3.Compared with oral digestion and gastric digestion,small intestine digestion has the greatest effect on total reducing sugar,free amino acids and fatty acids in peanut.Small intestine digestion can significantly increase the content of amino acids and total reducing sugar in peanut.The roasted peanuts contained more total reducing sugar than the raw peanuts,while the total amount of free amino acids have no remarkable change between raw and roasted peanuts.For the digestion characteristics of nutrients in raw peanuts and roasted peanuts,the roasting process can significantly increase the digestibility of lipids and reduce the digestibility of protein in peanut.There was no statistically significant difference of RDS and SDS between raw and roasted peanuts,but roasting could significantly increase the content of RS in peanut.Compared to raw peanuts,roasted peanuts have lower GI values.It can be seen that,just from the perspective of digestibility,peanuts have relatively high nutritional value after processing as oily seeds with high fat and high protein.4.By consulting a large number of literatures on the processing technology of yoghurt,this paper finally selected three factors: lactobacillus,sucrose content,and the ratio of peanut to milk.The three-factor and three-level orthogonal test design was adopted to optimize the formula of roasted peanut yogurt through the sensory evaluation of color,viscosity,acidity and flavor.The result show that 100 mL milk added 7 g of roasted peanuts,1 g of agar,6 g of sucrose,0.12 g of bacteria and fermented 6 h at 42 °C were the best technic for roasting peanut yogurt.The physicochemical properties and microbial indicators of peanut yogurt are in accordance with the national standards.