| The developing aquaculture industry in China has an increasing demand for varieties and output of feed.The dependence of import fish meal(FM)and soybean restricted the sustainable development of feed industry.At the same time,extrusion technology has gradually replaced the traditional granulation process.However,due to the short time and the lack of relevant research,at present,the extruded aquatic feed has not yet formed a systematic and complete process control system.There are common industrial issues such as lack of correlation between raw material characteristics,basic production and processing data,and disconnection between animal nutrition and actual production processes.Therefore,it is imperative to apply new protein resources and establish the digital and intelligent aquatic feed processing technology based on diversified formulas.This paper investigated the influence of processing characteristics and processing parameters of poultry by-product meal(PBM),pork meal(PM)and Methylococcus capsulatus,bath bacteria meal(Feed Kind?(FK))protein raw materials on the quality of floating aquatic expanded feed products and the correlation model was determined,the efficient and energy-saving production process parameters for producing low starch floating expanded feed using different new non grain protein sources were optimized and obtained,and providing reference for processing high-quality feed products and improving production efficiency.The details are as follows:(1)The study analyzed the differences and correlations in the physicochemical and processing characteristics of FM,PBM,PM,and FK raw materials using one-way analysis of variance,correlation analysis,and principal component analysis.The results showed that the tap bulk density of FM was the highest,but its p H and water solubility index were significantly lower than those of the other three raw materials.PBM had the highest pasting temperature,but its flow-figure and breakdown-viscosity were significantly lower than those of the other three raw materials.PM had the highest p H,but its water solubility index,protein dispersion index,water-soluble protein,foaming capacity,and foam stability were significantly lower than those of the other three raw materials.FK had significantly higher flow-figure,water-soluble protein,water absorption index,water solubility index,oil absorption capacity,protein dispersion index,foaming capacity,foam stability,peak viscosity,breakdown-viscosity,trough-viscosity,and emulsifying activity index than the other three raw materials,while its tap bulk density,setback,and pasting temperature were significantly lower than those of the other three raw materials.There were different degrees of correlation among the processing characteristic indicators of protein raw materials,and tap bulk density,setback,pasting temperature,and flow-figure were significantly positively correlated.They were significantly negatively correlated with water absorption index,trough-viscosity,peak viscosity,disintegration viscosity breakdown-viscosity,oil absorption capacity,emulsifying activity index,emulsifying stability,foaming capacity,foam stability,protein dispersion index,and water solubility index.(2)The study used response surface analysis(RSM)to investigate the effects of the replacement ratio of PBM for FM(0-100%),moisture content(23-32%),and die temperature(100-150 ℃)on the physical properties of low-starch floating aquatic feed,such as bulk density,expansion ratio,pellet hardness,water solubility,and hydration time.The results showed that as the replacement ratio of PBM for FM increased,the water solubility,maximum oil absorption,and expansion ratio of the feed significantly decreased,while the pellet durability index,pellet hardness,and bulk density significantly increased.As the moisture content increased,the water solubility,maximum oil absorption,and expansion ratio of the feed significantly increased,while the oil leakage,pellet hardness and bulk density significantly decreased.Under optimized conditions,such as ensuring that the feed has the bulk density of less than 450 g/L and the floatability of more than 98%,the best process parameters for producing low-starch floating aquatic feed by replacing FM with PBM were obtained through optimization: replacing FM with48.2-53.6% PBM(adding ratio of 19.3-21.4%),moisture content of 26.0-26.7%,and die temperature of 124.7-129.7℃.(3)Response surface analysis was used to study the effects of the replacement of FM with PM(0-100%),moisture content(23-32%),and die temperature(100-150°C)on the physical properties of low-starch floating aquatic feed.The results showed that as the proportion of PM replacing FM increased,the oil leakage,water solubility,maximum oil absorption,and expansion ratio of the feed decreased significantly,while the pellet durability index,hydration time,pellet hardness,and bulk density of the particles increased significantly.As the moisture content increased,the maximum oil absorption and expansion ratio of the feed increased significantly,while the pellet hardness,hydration time,and bulk density decreased significantly.As the die temperature increased,the bulk density decreased significantly,while the expansion ratio and maximum oil absorption increased significantly.The interaction between moisture content and die temperature,as well as between moisture content and replacement ratio,had a significant effect on water solubility.Under optimized conditions,such as ensuring that the feed has the bulk density of less than 450 g/L and the floatability of more than 98%,the best process parameters for producing low-starch floating aquatic feed by replacing FM with PM were obtained through optimization: replacing 3.6-13.3% FM with PM(adding ratio is 1.4-5.3%),moisture content is27.7-28.3%,and die temperature is 144.3-146.6°C.(4)Response surface analysis was used to explore the effects of the FK add ratio(0-9%),moisture content(23-32%),and die temperature(100-150°C)on the physical properties of lowstarch floating aquatic feed.The results showed that as the amount of FK added increased,the expansion ratio of the feed particles increased significantly,but the oil leakage,pellet durability index,and bulk density of the particles decreased significantly.As the moisture content increased,the maximum oil absorption and expansion ratio of the feed particles increased significantly,while the hydration time and bulk density decreased significantly.When the amount of FK added was relatively high(4.5-9%),the pellet durability index of the particles increased significantly as the moisture content increased.As the die temperature increased,the maximum oil absorption,oil leakage,and expansion ratio of the feed particles increased significantly,while the bulk density and hydration time decreased significantly.Under optimized conditions,such as ensuring that the feed has the bulk density of less than 450 g/L and the floatability of more than 98%,the best process parameters for producing low-starch floating aquatic feed by replacing FM with PM were obtained through optimization: adding 5.2-6.0% FK,moisture content is 24.3-24.9%,and die temperature is 127.6-136.7°C.(5)When PBM replaces FM to produce low-starch extruded aquatic feed,the effect on process parameters and energy consumption varies.When the proportion of PBM replacing FM is between 48.2% and 53.6%(adding ratio 19.3-21.4%),the production of each ton of feed reduces water consumption by 3.5-10.5kg,and the die temperature can be reduced by 10.4-15.4 ℃.The production of each ton of low-starch extruded aquatic feed can reduce total electricity consumption by 9.2-18.2 k Wh.Therefore,considering the experimental process parameter settings,optimization results,and energy consumption factors,PBM can be used as a substitute for FM to produce low-starch extruded aquatic feed,but the addition proportion needs to be controlled below21.4%.When the proportion of pork powder replacing FM is between 3.6% and 13.3%(adding ratio is 1.4-5.3%),the production of each ton of low-starch extruded aquatic feed requires an increase in total electricity consumption by 8.8-13.1 k Wh.Therefore,considering the experimental process parameter settings,optimization results,and energy consumption factors,PM is not conducive to being used as a substitute for FM to produce low-starch extruded aquatic feed.When the FK replaces FM,the water contents demand in feed production can be reduced by 23-27 kg per ton,and the die temperature can be reduced by 3.4-12.5 ℃.Adding 5.2-6.0% FK to the feed can reduce total electricity consumption by 21.6-30.5 k Wh per ton of low-starch extruded aquatic feed.Therefore,considering the experimental process parameter settings,optimization results,and energy consumption factors,FK is conducive to the production of low-starch extruded feed and can be used as a functional protein for processing low-starch extruded aquatic feed.(6)A quantitative correlation model between raw material processing characteristics and particle physical quality was established through partial least squares regression analysis,and it was determined that the water absorption index,p H,foaming capacity,foaming stability,water solubility index,setback,and oil absorption capacity of raw materials are key factors determining the physical quality of puffed products.The correlation between processing characteristics and particle physical quality are as follows: water solubility index is negatively correlated with pellet hardness and hydration time,and positively correlated with water solubility;The peak viscosity,setback,and breakdown-viscosity of the mixture of raw materials and flour are all negatively correlated with the floatability;The water solubility is negatively correlated with water absorption index,as well as with the peak viscosity,trough-viscosity,and breakdown-viscosity of the raw flour mixture;The oil absorption capacity is positively correlated with the maximum oil absorption and negatively correlated with the oil leakage;Foaming capacity and foam stability are negatively correlated with bulk density and pellet hardness,and positively correlated with maximum oil absorption;There is a positive correlation between water-soluble protein and floatability. |
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