Extrusion Process And Its Effect On Protein Of Sacha Inchi Cake

Sacha inchi is a perennial woody vine of the wild,half-timber,and big-branch families.Its seeds contain bioactive substances such as oils,proteins,amino acids,vitamins,and sterols.Sacha inchi cake is a direct by-product of the processing of the seeds of the vine.It has heavy astringency and bitterness and is difficult to eliminate.Currently,it is generally used as a waste or fish feed and cannot be used in food.However,the protein content of sacha inchi cake is as high as 59%,and the composition of amino acids is more comprehensive.It contains a variety of essential amino acids(such as cystine,tyrosine and threonine)and has high nutritional value.Difficulties in processing are not yet available in the food industry through extrusion.Based on this,this work intends to study the twin-screw extrusion process and its effect on sacha inchi cake protein,which can be used as a reference for the further processing of sacha inchi cake and the comprehensive utilization of food ingredients.The main research contents and conclusions are as follows:(1)The water holding capacity,oil retention,nitrogen solubility index,and sensory evaluation of the extrusion-structured sacha inchi cake were used as indicators to study the extrusion process parameters(water content,barrel zone III temperature,main motor rotation speed,and feed rate).The effect of extrusion extruding sacha inchi cakes was optimized by using response surface methodology to obtain the optimum parameters for the extruded sacha inchi cakes: 24% water content,115°C extrusion temperature III,feed rate 14 Hz,main motor speed 25 Hz.(2)The physicochemical and functional properties before and after extrusion of sacha inchi protein were studied and analyzed.The protein,fat and ash content of sacha inchi cake decreased after extrusion..After extrusion of sacha inchi protein,the nitrogen solubility index was retained after extrusion of sacha inchi protein.The contents of water-borne,oil-holding,foaming,emulsifying and free sulfhydryl groups decreased by 81.88%,4.95%,20.22%,64.71%,53.50%,and 31.50%,respectively.The in vitro digestibility of protein increased by 26.91%.After the amino acid content was squeezed,the amino acid had to be lost by 9.74% and the non-essential amino acid by 5.89%.Among the amino acids that lost more than 10% were threonine(26.97%),valine(12.32%),cystine(37.84%),methionine(48.99%),tyrosine(28.87%),and lysine(34.24%).The increase in amino acid content by more than 10% was glutamic acid(19.38%),phenylalanine(29.86%),histidine(11.55%),and arginine(27.65%).The isoelectric point of the protein decreased from 4.5 to 3 after extrusion,indicating that the extrusion process caused a certain degree of damage to the protein molecule;Fourier transform infrared(FTIR)spectroscopy analysis showed that the characteristic absorption of the protein before and after extrusion.There was no significant difference in the peaks.No new absorption band was found in the spectrum after extrusion,indicating that no new amide bonds were formed during the extrusion process;The peak temperature of the sacha inchi protein is higher and the thermal stability is higher,but the peak temperature of the protein after extrusion is lower,and the thermal stability is poor.The protein electrophoresis test shows that no new band is generated after the extrusion of sacha inchi protein.The color of the subunit strips is significantly lighter than before extrusion,but no subunit band disappeared,indicating that some degree of cross-linking polymerization reaction occurred during the extrusion process of methacin,resulting in some substances with relatively high molecular mass,which could not be dissolved in the sample buffer;through the microstructure observations showed that the protein before extrusion was present in the form of scattered,irregular macromolecules with small particles on the surface.After the extrusion,the original form of the protein was disrupted and the protein molecules became broken.Scattered,relatively small,irregular,blocky structures.(3)The formulation and technology of the new product of the energy sticks of sacha inchi were studied by using the extrusion powder of sacha inchi cake extrudates.Through the optimization of single factor and orthogonal test,the best formula for making the energy sticks of the cake was obtained by fuzzy mathematical sensory evaluation method: low gluten flour 37 g,the extrusion powder of 6g,white sugar 20 g,soybean oil 10 g,water 8g,soda 0.38 g,honey 4.8g,corn syrup 4.8g.