阅读说明：本技术 一种基于磷脂对鱼糜品质进行评价的方法 (Method for evaluating quality of minced fillet based on phospholipid ) 是由 林婉玲 韩迎雪 李来好 吴燕燕 杨贤庆 胡晓 黄卉 杨少玲 荣辉 于 2019-10-24 设计创作，主要内容包括：本发明提供了一种基于磷脂对鱼糜品质进行评价的方法,通过测定所选鱼种鱼肉的磷脂含量,根据磷脂含量与鱼糜凝胶强度的相关性模型,得到所选鱼种制成鱼糜的凝胶强度,对所选鱼种鱼糜品质进行评价并分等级。本发明基于磷脂对鱼糜品质进行评价的方法,通过磷脂含量就能计算得到鱼糜凝胶强度预测值,挑选到不同等级凝胶强度的淡水鱼鱼种,解决挑选做鱼糜鱼种的盲目性问题,使得挑选做鱼糜的鱼种过程简单,科学合理,有着广阔的开发和应用前景。(The invention provides a method for evaluating surimi quality based on phospholipid, which comprises the steps of measuring the phospholipid content of fish meat of selected fingerlings, obtaining the gel strength of surimi prepared from the selected fingerlings according to a correlation model of the phospholipid content and the gel strength of surimi, evaluating the surimi quality of the selected fingerlings and grading. According to the method for evaluating the surimi quality based on the phospholipid, the predicted value of the surimi gel strength can be calculated through the phospholipid content, freshwater fish species with different gel strengths are selected, the blindness problem of selection of surimi species is solved, the process of selecting the surimi species is simple, scientific and reasonable, and the method has wide development and application prospects.)

1. A method for evaluating the quality of minced fillet based on phospholipid is characterized in that the phospholipid content of fish meat of a selected fingerling is measured, the gel strength of minced fillet prepared from the selected fingerling is obtained according to a correlation model of the phospholipid content and the gel strength of the minced fillet, and the quality of the minced fillet of the selected fingerling is evaluated and graded.

2. The method for phospholipid-based evaluation of the quality of minced fillet according to claim 1, wherein the phospholipid is phosphatidylinositol.

3. The method for phospholipid-based minced fillet quality evaluation according to claim 2, wherein the correlation model of phospholipid content and minced fillet gel strength is as follows: y is 1992837.929 XPI⁶－5797864.735×PI⁵+6855877.258×PI⁴－4207477.195×PI³+1406390.867×PI²-240797279 XPI + 16900.136; wherein PI is the content of phosphatidylinositol in each gram of fish meat, and Y is the gel strength in mg and g cm.

Technical Field

The invention relates to a method for evaluating surimi quality based on phospholipids.

Background

Minced fillet is an intermediate product with a certain preservation period which is obtained by pretreating fresh raw material fish, then carrying out meat collection, rinsing, dehydration, fine filtration, split charging and freezing, is an indispensable raw material in the minced fillet industry, and is one of the important aquatic product processing varieties in China at present. The minced fillet product is prepared by adding auxiliary materials into minced fillet, and then carrying out processes of mincing, forming, heating and the like, and is more and more popular because the minced fillet product has good nutrition and flavor and is convenient to eat and carry.

At present, many indexes and methods for evaluating the quality of minced fillet and products thereof are provided. For a long time, the quality index of surimi and products generally comprises: the microorganism indexes, the sensory indexes and the physical and chemical indexes are shown in tables 1, 2 and 3, and refer to the national standard GB/T36187-2018. The gel property is the most important functional property of the quality of the minced fillet product processed by aquatic products, and the gel strength of the minced fillet product is the comprehensive embodiment of the elasticity, hardness, elasticity and viscosity of the formed minced fillet gel product and is the most main index for determining the minced fillet quality.

TABLE 1 quality index of minced fillet and its products

Item	Microbiological indicator	Sensory index	Physical and chemical indexes
					Colony count/(CFU/g)	Form (shape, size, tissue form)	Elasticity
Detecting items	Coliform group/(MPN/100 g)	Color and luster	Composition of ingredients
					Pathogenic bacteria	Flavor (I) and flavor (II)	Flavor (I) and flavor (II)

TABLE 2 sensory index of surimi

Item	Require that
		Color and luster	White, off-white
Form of the composition	The frozen block is complete and is in a uniform and smooth minced shape after being thawed
		Smell(s)	Has peculiar smell of fish, and has no peculiar smell
Impurities	No foreign impurities

TABLE 3 physicochemical indices of surimi

Besides the above-mentioned common indexes, the indexes capable of reflecting the quality of the minced fillet mainly comprise several aspects such as phospholipid type, content, texture index and the like. At present, the existing minced fillet evaluation method generally needs to process raw materials into minced fillet products and then measure gel strength and other indexes to judge whether the minced fillet processing is met according to the result, and mainly has the following defects:

(1) key factors closely related to the quality of minced fillet cannot be summarized to an evaluation result value, so that the accuracy of the evaluation method is insufficient;

(2) the gel strength range of any given fish can not be directly judged according to the raw material fish species;

(3) the fingerlings suitable for different grades of surimi cannot be screened out.

Disclosure of Invention

The invention aims to provide a method for evaluating the quality of minced fillet based on phospholipid, which solves the problem that whether the selected fish species are suitable for processing minced fillet cannot be directly judged from the aspect of fish raw materials in the prior art.

The purpose of the invention is realized by the following technical scheme:

a method for evaluating the quality of minced fillet based on phospholipid includes such steps as measuring the phospholipid content of fish meat of selected fingerling, obtaining the gel strength of minced fillet prepared from selected fingerling according to the correlation model between phospholipid content and gel strength of minced fillet, evaluating the minced fillet quality of selected fingerling, and grading.

Further, the phospholipid is phosphatidylinositol.

In the invention, the correlation model of the phospholipid content and the gel strength of the minced fillet is as follows:

Y＝1992837.929×PI⁶－5797864.735×PI⁵+6855877.258×PI⁴－4207477.195×PI³+1406390.867×PI²-240797279 XPI + 16900.136; wherein PI is the content of phosphatidylinositol in each gram of fish meat, and Y is the gel strength in mg and g cm.

Compared with the prior art, the invention has the following beneficial effects:

(1) the inventor of the invention discovers that the content of phospholipid is basically unchanged in the process of processing fish raw materials into surimi, obtains a method for evaluating the surimi quality based on the phospholipid according to a correlation model established by the phospholipid content and the surimi gel strength, can calculate and obtain a predicted value of the gel strength of the surimi prepared from the selected fingerlings by measuring the phospholipid content of the fish raw materials, and can know the gel strength of the surimi prepared from the fingerlings without preparing the surimi from the fish, so that the fingerlings of freshwater fish with different gel strengths can be selected, the blindness problem of selecting the fingerlings to be the surimi is solved, the process for selecting the fingerlings to be the surimi is simple, scientific and reasonable, and the method has wide development and application prospects.

(2) In the method, a correlation analysis method is adopted to determine the relation between minced fillet phospholipid and minced fillet quality in the model construction process, and finally a model relation is established for evaluating the minced fillet quality according to the significance; the method simultaneously utilizes two quality indexes of minced fillet phospholipid and gel strength, and has the advantages of scientificity, high accuracy and high stability.

(3) The method disclosed by the invention has the advantages that the time for selecting unknown fingerlings to prepare surimi is short, the speed is high, and the surimi can be prepared only by carrying out a small amount of calculation through a model.

Detailed Description

The present invention is further described below in conjunction with specific examples to better understand and implement the technical solutions of the present invention for those skilled in the art.

Test example: research on change conditions of various indexes of gel in minced fillet processing process

The differences in the gel properties of surimi are related to many factors, the most important of which are the species and the processing. Different fish species have different contents and different heat stability of myosin and myofibrillar protein, which directly influence the stability of the network structure formed in the gelation process of the minced fillet, and the heated activation degree and the effective activity of endogenous protease in the fish meat of different types of freshwater fish are different, so that the minced fillet produced by different types of freshwater fish has larger quality difference. The characteristic formation of the minced fillet is mainly related to myofibrillar protein, water-soluble protein is washed away after fish meat is rinsed, and a large amount of myofibrillar protein is exuded after the fish meat is mashed with salt. After low-temperature gelation and high-temperature gelation, hydrophobic groups in myofibrillar protein are exposed, a large number of hydrophobic groups are re-aggregated into a gel network structure, and water is contained in the network structure, so that the minced fillet has certain water retention.

In order to explore the reason for the difference in the quality of the minced fillet gel obtained by processing different species of fish, the experimental example takes two kinds of fresh water fish of tilapia and micropterus salmoides as objects, changes of indexes (total saturated fatty acid amount, total monounsaturated fatty acid amount, total polyunsaturated fatty acid amount, fat, phospholipid, malonaldehyde, disulfide bond and hydrophobic interaction) of the minced fillet gel from the rinsing and heating stages of raw materials are compared, the specific treatment process refers to example 1, and the experimental results are shown in table 4.

TABLE 4 minced fillet prepared from Tilapia and Micropterus salmoides

Note: sigma SFA is total amount of saturated fatty acid, sigma MUFA is total amount of monounsaturated fatty acid, and sigma PUFA is total amount of polyunsaturated fatty acid; -indicating that no detection was performed.

Results and analysis:

the raw material passes through the rinsing stage, sigma SFA and sigma MUFA are both reduced, sigma PUFA is increased, total fat content is reduced, phospholipid content is increased, and the ratio of polyunsaturated fatty acids in the surimi is higher than that in the raw material because most of lipid is removed in the rinsing stage and phospholipid part rich in polyunsaturated fatty acids is not easily removed. Through the heating stage, Σ MUFA decreases and Σ SFA and Σ PUFA content increases, because heating converts a portion of the monounsaturated fatty acids to saturated fatty acids; both fat and phospholipid content increased because there was cooking loss and moisture content decreased during cooking. Malondialdehyde is the end product of lipid oxidation, and its interaction with protein molecules results in the formation of protein aggregates, which affect the formation of surimi gel. From the change of malondialdehyde in the course of tilapia and weever, the heating phase promotes lipid oxidation more easily than the rinsing phase. Under the same conditions, the fat content and the phospholipid content of tilapia and micropterus salmoides are higher in the heating stage, so that the oxidation degree is higher, and the malondialdehyde content is higher, so that the gel strength is not as good as that of tilapia surimi gel.

Disulfide bonds are mainly formed in the heating process during the processing of the surimi, so that only heated surimi gel is measured. Generally, the higher the disulfide bond content, the greater the hydrophobic interaction, and the better the surimi gel properties. The disulfide bond content of the tilapia is higher than that of the micropterus salmoides, so the tilapia surimi gel strength is higher than that of the micropterus salmoides gel. The hydrophobic forces tend to increase during the minced fillet rinsing and heating process, with the heating stage having the greatest effect on the hydrophobic forces of the minced fillet gel. This is because the hydrophobic forces during the processing of surimi gels are primarily determined by the polarity of the amino acids. Through the heating process, the conformation of the protein begins to change, the nonpolar amino acid begins to be exposed, the hydrophobic acting force is enhanced, the hydrophobic groups can be mutually aggregated along with the increase of the exposure of the hydrophobic amino acid, the hydrophobic acting force is increased, and the larger the hydrophobic acting force is, the better the minced fillet gel characteristic is.

The inventors of the present invention have made the above-mentioned studies and confirmed that phospholipids in surimi, which are lipid substances mainly contained in muscles, are bound to lipids without being washed out during the processing of surimi, and are always present during the processing of surimi, and the content of phospholipids in surimi is substantially maintained during the processing. Therefore, the use of phospholipids as surimi quality assessments is feasible.

The model construction process of the method for evaluating the quality of minced fillet based on phospholipid is as follows:

(1) selecting phospholipid composition as minced fillet evaluation indexes, selecting gel strength, hardness and elasticity as minced fillet quality indexes, and respectively measuring the phospholipid content, the gel strength, the hardness and the elasticity of 30 kinds of minced fillets;

(2) through the correlation analysis of surimi evaluation indexes and surimi quality indexes, certain relation between Phosphoinositides (PI) in surimi and surimi gel strength is obtained according to the significance of results;

(3) the evaluation model is established as Y-1992837.929 XPI⁶－5797864.735×PI⁵+6855877.258×PI⁴－4207477.195×PI³+1406390.867×PI²-240797279 XPI + 16900.136; wherein PI is the content of phosphatidylinositol in each gram of fish meat, and Y is the gel strength in mg and g cm.