Quick Quality Tests for Protein Meals

QUICK QUALITY TESTS FOR PROTEIN MEALS Dr. Jowaman Khajarern and Dr. Sarote Khajarern Department of Animal Science, Faculty of Agriculture Khon Kaen University, Thailand INTRODUCTION

Since the early 1970s, the feed industry in Southeast Asia has made tremendous expansion. High quality materials especially protein meals (fish meal and soybean meal) are often in short supply and also exhibit a variation in the quality aspects of nutrient availability. Since prot ein sources especially fish meal and soybean meal generally have high unit cost, the company must establish written ingredient quality standards for purchasing, but the methods for examining the physical qualities, especially for foreign materials and evidence of mold, must be fast, accurate and practical by the operators at the receiving plant. The operators must be trained to recognize and understand the quality of raw material to perform their visual and other quick physical and chemical examinations, and in the proper methods of sampling. The objective of this paper is to highlight the most important method of quick tests for protein meals used for the purchasing of the raw materials. Sources of Protein Meals Meals for Non-rum inants and Aquacult ure Sources Plant Protein ----------------------------------------------------------------------------Conventional Major Soybean meal Fullfat soybean Sunflower meal Sesame meal Peanut meal Canola and Rapeseed meal Corn gluten meal Palm kernel meal Copra meal ----------------------------------------------------------------------------Minor Soya protein isolate Wheat gluten meal Mung bean Potato protein Cotton seed meal Kapok seed meal

Animal Protein

Fish meal Meat meal Meat and bone meal Milk products Poultry byproducts

Feather meal Blood meal Marine soluble products Shrimp products Squid products Yeast

----------------------------------------------------------------------------Non-conventional Rubber seed meal Leather meal Lupins Safflower meal Linseed meal Field peas Mustard meal Cocoa seed meal

Silk worm pupa meal Crab products Lard pulp Brewer's byproducts Distiller's byproducts

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Quality Control i n Different Protein Meals --------------------------------------------------------------------------------------------Ingredient Quality Physical characteristics (analyst's skills): color, texture, odor and (Qualitative) taste, particle size (screen analysis), shape, adulteration, damage and deterioration, bulk density, spot and quick chemical tests. --------------------------------------------------------------------------------------------Ingredient Quality Proximate analysis: moisture, CP, CF, EE, NFE, ash, silica or

(Quantitative)

sand, salts etc. Protein quality: protein solubility or dispersibility, bitrogen solubility, mailard reaction product, biogenic amines, trypsin inhibitor activity, urease activity, dye binding, pepsin digestibility, urea and nonprotein nitrogen.  Amino acid: composition, digestibility, availability  Anti-nutritional factors: - Extrinsic (contaminants): mycotoxins, insects, weeds, insecticide, herbicides, fungicides. - Intrinsic: allergins, lectins, phytoestrogens, glucosinolate, saponins, tannins, ricin, sinapine, gossypol, lipoxygenase. Decomposition and rancidity test: acid value, peroxide value, etc. --------------------------------------------------------------------------------------------Quick Test for Fish Meal Quality Control

Basically, fish meal is produced from two types of raw materials, fish wastes from human food industry and whole fish. Differences in composition of fish meal may be attributed to many causes: variation in raw materials, differences in processes, contamination of raw materials with some waste products or with sand, impurities, excessive salts and/or fat content or excessive moisture, adulteration with other sources of meal, meat and bone meal, plant proteins, etc. Fish meal is also prone to contamination with biogenic amine and gizzarosine found during processing and storage that have been allowed to spoil or putrefy and have dramatic impact on the quality and nutritive composition of fish meal. The main aspects of quality control for consideration are:  

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Raw material type:  whole fish or trimmings Processing temperature: low temperature (LT) high temperature (HT) on digestibility of protein and over-heated by using racemization of aspartic acid (Luzanna et al., 1996) to indicate digestibility of protein and a simple dilute pepsin test (strength 0.0002 %) at 450C will identify overheated fish meal. Freshness of raw material: Fish spoils protein breakdown to amines (histamine, cadaverine putrescine and tyramine). The sum of the four should be less than 2,000 ppm or predominant in anchovy, mackerel, sardine, etc. or cadaverine predominant in capelin, sandeel, sprat, etc). Lipid quality: Oxidation of fat to free fatty acids given a crude measure of fish freshness. Oxidation of fat can reduce growth of animal and aquaculture. Ethoxyquin has been found to be the most effective antioxidant. Free fatty acid (FFA) peroxide value (PV) and quick test for rancidity should be assessed for quality control. Microbial standards: Fish meal should be free of salmonella and mycotoxin. Because carbohydrate or starch is absent, mold growth generally does not occur if fish meal is properly stored in dry conditions and stabilized with antioxidants.

Quick Test for Quality Grade of Fish Meal 1. Place 10g of fish meal in a 100 ml tall form beaker and pour 80 ml carbon tetrachloride into the beaker, stir and allow to settle (5 min.). 2. Scrape off the floating organic fraction with stainless steel spoon into filter paper. Clean off the side of the beaker and spoon and then pour off the liquid to separate floating and the submerged fraction into the filter paper. 3. Place the two fractions into a 110 0C oven for 10 min. then allow to cool and weigh each fraction. 4. The approximate percentage of organic (fish flesh) and inorganic (fish bone) may be calculated. Shrimp and Salmon Grade Fish meal Grade A (CP>70%) Fish meal Grade B (CP>65%)

Inorganic Fraction