A Study On Whey Vinegar And Its Effect On The Immunity Of Rats

Milk whey is the byproduct of producing cheese and casein. It contains nutrients, including lactose, whey protein, minerals and vitamins, and has important physiological features. However, due to the low concentration of dry matter in the milk whey, the complexity of its development and utilization, and the high cost of the equipment used in the concentration process, many cheese producers often discharge milk whey as wastewater. This is not only a waste of resources, but is also an environmental pollutant. Therefore, to scientifically develop and utilize milk whey resources, this dissertation discusses the milk whey product that results from deep fermentation, that is, milk whey vinegar.This product will not only meet consumers'increasing demand for healthy foods, but also provide a new solution for the cheese production industry, by manufacturing a valuable product from a byproduct of the cheese-making process. Currently, there is very little research conducted on the development of milk whey worldwide. Therefore, the study discussed in this dissertation contributes significantly to the growth of the milk whey industry.This dissertation discusses milk whey fermentation techniques and analyzes the flavor substances and some of the nutritional components of whey vinegar. Additionally, laboratory tests show that whey vinegar has a significant effect on building up the immune system of rats. The research study methodology and results are as follows:1. The liquid-state fermentation method was adopted to produce whey vinegar. The Plackett-Burman Test was employed to determine the factors that play important roles in the fermentation process, both at the alcohol and acetic acid stages. The Fast-Rising Test was used to determine the most optimal factors at the alcoholic and acetic acid stages of the fermentation process. The Box-Behnken Test was employed to determine the two optimal conditions for the fermentation process. Test results show that the optimal conditions for alcohol fermentation are:(A) a dosage of kluyveromyces marxianus4x106cfu/ml,(B) a dosage of saccharomyces cerevisiae4.5×106cfu/ml,(C) fermentation time151h,(D) a dosage of lactobacillus rhamnosus2×106cfu/ml,(E) a dosage of lactobacillus delbrueckii subsp. bulgaricus2×106cfu/ml,(F) temperature40?,(G) sugar concentration40%,(H) initial pH6.1, and(I) ginger power0.095(g/100ml). The optimal conditions for the acetic fermentation are:(A) temperature30?,(B) initial pH5.7,(C) ethanol concentration7.0,(D) fermentation time617h,(E) a dosage of acetobacter sp.6.5×106cfu/ml, and(F) a dosage of acetobacter pasteurianus subsp.6.5×106cfu/ml.2. The Solid-Phase Micro-Extraction Fibers and the Gas Chromatography-Mass Spectrometry (GC-MS) tests were performed to extract the volatile compounds of whey vinegar and analyze their nutritional components.The results of the extraction and analysis show that36volatile compounds were identified (match rate at80%and above). These compounds were classified into7categories including5esters,5acids,4ketones, 10alcohols,6aldehydes,2phenols and4paraffins. Amino-acid Analysis was adopted to detect the existence of free amino acids in the whey vinegar. The result reveals the existence of25types of amino acids. Eight (8) types of these amino acids are essential to the health of humans and4types, including lysine, threonine, arginine, serine, et cetera, can enhance the immune system of humans.A test was performed on the16mineral and vitamin contents in the whey vinegar. The result shows that whey vinegar contains a lower level of Chlorine, Sodium and Iron than those in white rice vinegar and apple cider vinegar, but contains a higher level of potassium, calcium, magnesium, zinc, manganese, iodine, phosphorus, selenium, VB1, VB2, Vc, VA, and VE than Those in white rice vinegar and apple cider vinegar.3. An animal laboratory test was conducted to see if whey vinegar could improve the immune system of a common rat. the results are as follows:(1) The ratio of internal organ to body weight test:Compared with control groups, the dosage feeding groups (experimental groups) at high and mid-levels of feeding show statistically significant enhancement of weight in immune organs and statistically significant enhancement of thymus and spleen indexes (P<0.05).(2) The test of delayed hypersensitivity in rats induced by dinitrofluorobenzene: Compared with control groups, the dosage feeding groups (experimental groups) at high, mid-and low levels of feeding show statistically significant differences in ear swelling of rats (P<0.05), an indicator that whey vinegar can significantly increase delayed hypersensitivity in rats.(3) The test of lymphocyte transformation induced by ConA:Compared with control groups, the dosage feeding groups (experimental groups) at high, mid-and low levels of feeding show statistically significant enhancement in lymphocyte proliferation (P<0.01).(4) The test of antibody-forming cells:Compared with control groups:the dosage-feeding groups (experimental groups) at high, mid-and low levels of feeding show that whey vinegar has no statistically significant effect on antibody forming cells.(5) The test of serum hemolysin:Compared with control groups, the dosage feeding groups (experimental groups) at high, mid-and low levels of feeding show that whey vinegar has no statistically significant effect on serum hemolysin, or on antibody formation level.(6) The test of phagocytosis of chicken red blood cells in mice peritoneal macrophages:Compared with control groups, the dosage feeding groups (experimental groups) at high and mid-levels of feeding show that whey vinegar can effect statistically significant enhancement of rats'macrophage phagocytosis ability to attack and swallow (P?0.01).(7) The test of carbon clearance:Compared with control groups, the dosage feeding groups (experimental groups) at high, mid-and low levels of feeding show that whey vinegar can effect statistically significant increases in rats'swallow indexes (P?0.05).(8) The determination of the activity of NK cells:Compared with control groups, the dosage feeding groups (experimental groups) at high, mid-and low levels of feeding show that whey vinegar can effect statistically significant enhancement of the activity of NK cells in rats(P?0.01).In conclusion, whey vinegar can be successfully produced from milk whey, with liquid state fermentation process at the alcoholic and acetic acid stages. Whey vinegar contains a higher level of nutrients than a regular white rice or apple cider vinegar. In addition, whey vinegar is rich in flavor. Finally, whey vinegar can significantly improve a rat's immunity.