Brewing And Quality Analysis Of Broad Bean Paste Based On Extrusion Technology

Broad bean paste is a traditional fermented product in China,which is widely favored by consumers because of its delicious fragrance and rich nutrition.However,the ripening process used in the production of traditional broad bean paste faces the problems such as varying degrees of material ripening,long fermentation period,unstable quality.Besides,there are problems such as high cooking energy consumption and serious wastewater pollution.As a high-efficiency,green and continuous grain ripening technology,extrusion technology can replace traditional cooking technology and has been used in traditional liquor,rice wine,soy sauce and beer industries.Therefore,this study intended to introduce extrusion technology in the production of traditional broad bean paste,improve the traditional broad bean paste brewing process,thereby improving the quality of broad bean paste,and providing effective extrusion control parameters for the upgrading of the traditional broad bean paste process.The difference in the physical/chemical properties of materials treated by extrusion and those treated by steam-cooking methods was investigated.Results showed that during extrusion,the content of crude starch decreased,and the soluble protein content,gelatinization degree,ash content,water absorption index and water solubility index increased.A network porous structure in the extruded samples was observed by SEM.Furthermore,the CLSM results showed that the starch of the extrudate was embedded well in its protein network.CD spectroscopy implied that the ?-helix decreased while the ?-turn and random coil increased after both treatments.Mw analysis determined that the starch molecules were degraded during extrusion,the proportion of micromolecules was more in the extruded samples than in the steam-cooked samples.However,the chain length distribution of starch exhibited no significant difference between the extruded and steam-cooked broad beans.All the results showed that the state and properties of extruded materials were greatly different from those of steam-cooking materials.The porous structure formed in extruded materials was beneficial to the subsequent koji-making process.The characteristics of material structure can be changed based on extrusion treatment,the effects of extrusion parameters(screw speed,wheat flour addition,barrel temperature,moisture content of ingredient)on the activity of the enzyme were studied.The neutral protease activity,alkaline protease activity,glucoamylase activity were regarded as the indexes.The process conditions were optimized by the single factor experiment and the response surface methodology(RSM).The operating conditions of extrusion were optimized as follows: the screw speed,100~120 r/min;the wheat flour addition ratio,17%~26%;the barrel temperature,115~130°C;the moisture content of the material,45%~48%.Under these conditions,the optimal neutral protease activity,alkaline protease activity and glucoamylase activity were 1331.91 U/g,532.30 U/g and 93.25 U/g,respectively.The material used for broad bean paste was treated by the optimum extrusion conditions,the fermentation process conditions(fermentation time,fermentation temperature and salt addition)suitable for extrusion pretreatment of raw materials were optimized by the single factor experiment and the response surface methodology(RSM).The content of amino nitrogen was regarded as main indicator.The results showed that the amino acid nitrogen content in broad bean paste was the highest at 0.89 g/100 g when the fermentation time was 25 days,the fermentation temperature was 38°C,and the salt addition was 11%,which was 30.88% higher than that of traditional cooking.The content of amino acid nitrogen,total nitrogen and L value in broad bean paste brewed by extruded marerial were higher than those of traditional steam-cooked material.Based on the above research,the edible quality and flavor properties of broad bean pastes were evaluated.The edible quality and the flavor of different broad bean pastes were analyzed by the automatic amino acid analyzer,HS-SPME-GC-MS,electronic nose technology and sensory evaluation.The results showed that the nutritional value of the protein in extruded samples,cooked samples,and commercial samples was similar,and they all could satisfy the needs of the human body for the amino acid ratio.The delicious amino acid ratio and the aromatic amino acid ratio of the extruded samples were closer to those of the commercial samples.The types of volatile flavor substances were 63 in the extruded samples.There were 42 volatile flavor substances in the steamcooking samples.There were 46 volatile compounds in the commercial samples.Esters,alcohols,aldehydes and nitrogenous compounds played an important role in the aroma.The flavor components of the three samples were measured by electronic nose technology,the sensory evaluation of broad bean pastes was made.Overall,the extruded samples were closer to the commercial samples,and the overall acceptability was higher.In summary,this paper focused on the application of extrusion technology in the improvement of raw material quality and the production of broad bean paste.The whole process was green and pollution-free,and the fermentation cycle was shortened.The extruded products were closer to the commercial products in terms of quality and flavor.This paper also provided ideas and theoretical support for the production of traditional broad bean paste.