Nutritional Evaluation Of Protein Powder And Anti-Aging Study In Aged Rats

IntroductionAlong with the development of the social health industry, protein powders are gradually emerging in the supermarket, drugstore and common households as a new health care product. Protein powder (PP) is high quality protein, so it’s convenient to take, low in fat and low in cholesterol. Long-term consumption of PP does not cause wealthy diseases like obesity, hyperlipidemia and cardia-cerebrovascular disease. At present, most of the protein powder products on the market are made of soybean protein and whey protein. Therefore, this project aim to study on compound PP which main consisting of soy protein and whey protein. Determine its ingredients and analyzes the effectiveness it might have. Do growth experiments in infant rats to evaluate the protein quality. Give PP supplements to aged rats, measure the immunity and anti-oxidation indexes, analyze its influence on rat aging. This article aims to through comprehensive study of compound PP nutritional value and anti-aging effect on aged rats, provide experiment basis for the effectiveness of related health food. PART I Nutritional evaluation of protein powder(1) Ingredient analysis research of test Protein powderObjectiveAnalysis the nutritional and efficacy ingredient of test protein powder, including crude protein, crude fat, carbohydrate, crude fiber and other major nutrient contents,9kinds of macro elements and trace elements,3kinds of fat-soluble vitamins,3kinds of water-soluble vitamins and18kinds of amino acids, phospholipid, bioactive components mainly include soy isoflavones, total saponins and other phytochemicals, analysis its characteristic of components, lay the foundation for subsequent study of its nutrition physiological function.MethodsProtein powder’s nutrition ingredients was tested according to national standard methods or internationally recognized methods, test data was compared with main source of food for high quality protein in<the China food composition table2002>(such as meat, eggs, milk, etc.), to comprehensive evaluation of protein powder’s nutritional value. Testing items included protein, amino acid, crude fat, fatty acid, phospholipid, carbohydrates, crude fiber, vitamin A, D, E, folic acid, choline, biotin, calcium, magnesium, potassium, sodium, iron, copper, zinc, selenium, manganese, total saponin and soy isoflavone.ResultsProtein content of protein powder is close to80.0%. Essential amino acids (EAA) content is quite high, has a large percentage of all tested amino acids, a total of41.62%. Branched chain amino acids (BCAA) comprised about20%of total protein content. Ratio of BCAA to aromatic amino acid (AAA) is2.05. Amino acid score (AAS), chemical score (CS) of test protein powder was86.3,59.6. Total fat content of protein powder was3.32%. Essential fatty acids (linoleic acid) content is 45.69%, ratio of unsaturated fatty acids to saturated fatty acid is about2:1(1.93:1),3kinds of fatty acids ratio, PUFA:MUFA:SFA=1.36:0.59:1.Phospholipid content is2.7%, this result points to PP has a centain amount of phospholipid. The carbohydrate content of test PP is1.02g/100g. Crude fiber content<0.5g/100g. Calculation method is used to get protein calories as1480KJ/100g (or354Kcal/100g). Vitamin A content is12.3g/100g, vitamin D content<1μg/100g, vitamin E content is1.28mg/100g, choline content is203mg/100g, the content of biotin<2.0μg/100g, the content of folic acid is359μg/100g. The content of macro element calcium, magnesium, potassium, sodium respectively,161,59.7,413,370(mg/100g), the content of trace elements iron, copper, zinc, selenium, manganese respectively are9.18mg/100g,0.945mg/100g,2.5mg/100g,0.936mg/100g,10.0μg/100g. Total saponins content is0.98g/100g, the content of soy isoflavones is37.56mg/100g.ConclusionThe test protein powder has high protein content, reasonable amino acid composition pattern which is close to the FAO/WHO pattern, and high in EAA and BCAA contents. AAS and CS of PP are higher than soybean protein isolates, etc. The test PP is low in fat, has a number of phospholipid. The test PP is also has choline, folic acid, iron, zinc, selenium and other micronutrients, and bioactive components such as soy isoflavones and total saponins. This result pointed to the test PP is scientific ingredient of soy protein and whey protein and remained efficiency ingredients as much as possible in the machining process. (2) Nutritional evaluation of protein powderObjectiveTo evaluate the protein quality of PP through animal experiments, including Protein efficiency ratio (PER) test and nitrogen metabolism tests. In all growth rate methods, PER test has been used broadest. This method has been widely used to predict protein quality needed by the human. In1990, the United States FDA determined it as a protein evaluation method in Nutritional Labeling and Education Act (NLEA). For the evaluation of nitrogen balance, in common use digestibility, biological value (BV) and net protein utilization (NPU). According to the growth conditions of rats and these common indexes to evaluate the nutrition value of PP and compare with other high quality protein, so the results will be comprehensive.Methods1. PER test:Preparation experiment animal feed reference to AOAC method of protein efficiency ratio (PER) feed formulation and measure its protein content. Experimental subject is laboratory SPF wistar rats, males, early weaning; about40g of body weight.36rats were divided into3groups by randomized block method,12in each group. Mean weight difference between groups less than5g, weight difference in the group less than10g. After3d acclimatization phase, rats enter the experimental period. In experimental period, give different group different formulation feed, detect and observe related targets. Each rat was raised in single cage, take food and water freely, record body weight and body length in every3d and every weekend. The experimental period continued28d.2. Digestibility test:Use12infancy wistar rats which body weight approximately180g, move each rat into single metabolic cage. After acclimatization, divide rats into2groups, every group has6rats. Mean weight difference between groups less than5g. Feed experimental group the test feed, feed control group N-free (nitrogen-free) feed. Provide enough water, but feed intake was conditioned to15g/d. Feed experimental feed9d and collect spilled food, fecal and urine in last5d, assay fecal nitrogen and urinary nitrogen with kjeldah method. Calculate the PER, correction PER, apparent digestibility, true digestibility, biological value (BV) and net protein utilization (NPU) according to the formula.ResultsThe rat growth experiment showed food utilization rate in protein group and casein group have no significant difference (P=0.365). PER of test PP is2.22±0.08, apparent digestibility (AD) and true digestibility (TD) respectively are99.45%and99.46%. Biological value (BV) is93.14, net protein utilization (NPU) is92.60%, approach casein.ConclusionAnimal experimental results showed that rats have good digestion and absorption of protein powder, the test PP can obviously promote animal growth and maintain the balance of nitrogen metabolism. The PER of protein powder are nearly with casein, the evaluation indexes like digestibility, BV, NPU of protein powder are quite high. So the protein from test protein powder has high nutritional value. PART Ⅱ Anti-aging study of Protein powder in aged rats ObjectiveExisting literatures and the preliminary research in this project are all suggest that the amino acid composition characteristic and functional component of test PP have contribute to anti-oxidation and improve the body’s immune function. Currently, there are rare reports about PP supplementation for the aged people’s nutritional condition, antioxidant effect and immune function influence. Along with the speedup of aging in our society, it is necessary to study protein supplements and other anti-oxidation, anti-aging health care products. This project aim to observe the influence of PP supplementation in aged rats on nutritional biochemical indexes and anti-oxidation, immune function, provide theoretical basis for the development of protein powder health food.Methods40female12months of age rats were randomly divided into4groups:control group and protein powder low-dose (PPL,0.167g/kg.bw), medial-dose (PPM,0.833g/kg.bw), high-dose (PPH,1.667g/kg.bw) group. The control group was given a gavage of distilled water, other group were given a gavage of protein powder turbid liquid of different dose,1/d for60d. After experiment, get blood from heart and detect the biochemical indicators and antioxidant, immune indexes, including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), lactic dehydrogenase (LDH), immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM), T cell subset CD3, CD4, CD8levels and interleukin-2(IL-2), etc. Measure the weight of brain, liver, kidney, spleen, thymus, etc. and determine the total protein content, lipofuscin (LF) content and monoamine oxidase (MAO) activity of brain, and determine main lipids level in liver and lipase activity, etc.Results1. Rats of experimental groups have significantly higher serum total protein and total iron binding capacity (TIBC), PPH group has significantly lower serum TC than control group. The liver total cholesterol (TC) content in aged rats of experimental groups is significantly lower than control group (F=4.977, P=0.006). The liver TG content of experimental groups rats are lower than control group, but the difference was not statistically significant. PP supplementation has not showed significant difference on body weight in aged rats, but in the experimental group, rat brain, liver and kidney total protein content is higher than control group. The LDH activity of PPM and PPH group is lower than control group, but the difference was not statistically significant. Serum AKP (Alkaline phosphatase), APT (Alanine aminotransferase) and AST (Aspartate aminotransferase) activity of aged rats was almost not influenced by PP supplementation. The results suggest that test PP can improve total protein content in serum and organ of aged rats, and has positive meaning for aged rats liver lipid metabolism.2. PP supplementation can improve SOD activity in serum of aged rats, reduce MDA content. The SOD activity of PPM and PPH group is significantly higher than control group (P=0.014, P=0.005), MDA of PPL and PPM group is significantly lower than control group (P=0.024, P=0.024). Brain MAO of PPM group is significantly lower (P=0.037). The results suggest that appropriate amount of PP supplementation has some antioxidant and anti-aging effect on aged rats.3. The spleen index of PPL and PPM group is higher than control group, the difference was statistically significant (F=0.037, P=0.029). The thymus index of experimental group is higher than control group, but it was not statistically significant. PP supplementation has some influence on rat humoral immune function. The serum IgM level in experimental groups was significantly higher than control group (F=20.896, P=0.000), serum IgM level increased significantly in PPM and PPH group (P<0.05). In addition, serum IgA, IgG levels in experimental groups were higher than the control group, but there was no statistically significance.PP supplementation has some improvement to rat cell immune function. The serum T cell subset CD3, CD4, CD8levels of experimental group rats were significantly increased (F=40.474, P=0.000; F=55.947, P=0.000; F=200.234, P=0.000), and increased with the increase of PP supplement dose. In addition, the serum IL-2content of experimental groups is significantly increased (F=74.531, P=74.531). The results suggest that PP supplementation help to improve immune function of aged rats.ConclusionTest PP supplementation can increase the total content in aged rats serum and organ, improve nutritional status in aged organism, and has positive meaning for aged rats liver lipid metabolism. The test PP has some antioxidant effect on aged rats, a balanced amount of PP supplementation can increase the activity of serum SOD in aged rats and reduce the MDA content and brain MAO activity. The test PP has improvement to immune function of aged rats.Anyhow, appropriate amount of protein powder supplementation can improve the nutritional status of aged rats and have improvement to immune function, antioxidant and anti-aging effect.