Microsoft word - o 2003.doc

Product and Process Research Center,based on the research fields, consists of 7 working groups, namely Chinese Food Technology, Food Lipids and Phyto-chemicals, Immuno-biochemistry, Process Chemistry, Biopolymer Process, Packaging and Preservation, and Thermal Processing. The achievements and the important findings derived from various research projects in the year 2003 are summarized as follows. I. Technologies for Production of Functional Foods and Ingredients
1. Development of hypolipidemic peptide ingredients
Peptides are polymers of amino acids with different chain lengths. They are also the metabolic intermediates of proteins in physiological system. Besides as excellent carriers of amino acids in human nutrition (for example: glutamine peptides), peptides also possess various biological functions (for example: hypolipidemic effect or hypertension inhibition) that help maintaining the body health. In recent years, with the sophisticated development of commercial enzymes and fermentation technology, peptides have gradually become the major target in product development which was previously dominated by amino acids in the fields of human nutrition and seasoning industry. In this study, proteins from pig red blood cell were hydrolyzed with suitable proteolytic enzymes to release Val-Thr-Leu (VTL), Val-Tyr-Pro (VYP) or Val-Val-Tyr-Pro (VVYP), the major hypertriglyceridemia inhibitory peptides from hydrolyzed pig red cell. It was found that the acidic protease had better hydrolytic ability than the alkaline protease in releasing VTL, especially at low degree of hydrolysis. The alkaline protease, on the other hand, showed higher ability to release VYP than the acidic protease. However, the difference was apparent only at higher concentration of protease treatments. The alkaline protease also had higher ability to release VVYP at low concentration of protease treatments, but the acidic protease gave much higher VVYP concentration at high concentration of protease treatments. Because the anti-hypertriglyceridemia activity of VVYP is 15 or 6 folds to those of VTL or VYP, respectively, it is believed that the acidic protease is much more important than the alkaline protease in hydrolyzing pig red blood cell proteins in terms of 2. A Technique for Isolation of Hypocotyls from Soybeans
Isoflavones are naturally occurring plant compounds found rich in soybeans. Plant compounds that have estrogen-like properties are called phytoestrogens. Most isoflavones have phytoestrogenic properties. Isoflavones have been shown to have beneficial effects on cardiovascular function, relief of menopause symptoms and prevention of osteoporosis and endocrine-responsive cancers. Hypocotyls contain much more isoflavones than the other parts of soybeans. Hence our study is aimed to develop a process that can quickly and effectively separate the hypocotyls from the cotyledons of soybeans. A collision process was found capable of doing the job. The purity and recovery of hypocotyl products obtained by this process are found to be more than 85% and 60% respectively. Numerous positive effects of isoflavones on antioxidation, antitumor, reduction of bone loss and relief of menopausal symptoms have been reported. All these evidences showed that isoflavone could be used as potential ingredients for health food production. In Taiwan, the middle-aged population, the potential target consumers of isoflavones, is more than 5.7 million. Based on the demand of 40-50 mg isoflavone glucosides by each person per day, the estimated domestic demand of hypocotyls could be at least 4,000 tons per year. 3.Development of Chinese Medicated Foods and Evaluation of Their
Immunomodulation Functions (Ⅱ)
Last year the commercial production methods for 11 Chinese medicated foods were developed in this study and the immuno-modulation functions of these medicated foods were also tested. The project of this year was to continue the study on the commercial production methods for another 8 different Chinese medicated foods and the evaluation of their immuno-modulation functions. The sensory evaluation indicated that these 8 Chinese medicated foods prepared in this study were all well acceptable and the in vitro immuno-modulation tests showed that all these 8 medicated foods were capable of enhancing the cell(J774A.1) phagocytosis activity and the proliferation of lymphocytes. In addition, one of the 8 medicated foods, namely beef soup with lotus, wolfiporia cucos and dates, was further evaluated for its in vivo immuno-modulatory effects. The test showed that the blood phagocytosis activity in BALB/c mices fed with this medicated beef soup was found significantly higher than that of control mices. But the natural killer cell activity in spleen was not significantly different between them. Also the proliferation of lymphocytes could be enhanced in BALB/c mices fed with the medicated beef II. Functionality Assessment of Functional Foods
1. Primary rat hepatocytes as an alcohol-induced oxidative stress model
The use of cell models is an indispensable tool of current research into the screening for bioactive compounds. Our task of this project was to assess primary rat hepatocytes for their suitability in hepatoprotective studies based upon the effects of alcohol on cell viability, oxidative stress indices and gene expression levels of CYP450 family members and of other liver damage indices. time-dependently increased in alcohol-induced hepatocytes. Cellular glutathione concentration was reduced after 24-h incubation with 1% of alcohol. While the expression levels of CYP2E1 and CYP4A3 genes increased after 15 min of incubation and peaked at 2 h, the protein concentrations of CYP1A2 and CYP3A1 reached the highest after 6 h and increased with the concentrations of alcohol. Both gene expressions and protein concentrations of CYP family members showed a dose- and time-dependent relationship in alcohol-induced hepatocytes. The activities of CYP2E1 approximately doubled in 1% of alcohol after 24 h. Expression levels of liver damage markers such asá-feto protein, selectin and CD14 were also significantly increased. In summary, the results of present study suggested that primary rat hepatocytes as an alcohol-induced oxidative stress model could be used for screening hepatoprotective compounds. 2.The gastroprotective effects of a complex plant extract drink
A complex plant extract (CPE) drink developed by this Institute was evaluated for cytoprotective activity on peptic ulcer in male Wistar rats. Chronic ulcer was induced by applying 0.02ml of 20% acetic acid onto serosa of the stomach, 3 days later 3ml of deionized water (H), a commercial product (MP) or CPE were orally given for 5 days. Acute ulcer was induced by oral gavage either of 1ml/rat of 95% ethanol/0.35N HCl, 200mg/kg aspirin/0.35N HCl, or 250mg/kg indomethacin. One hour after oral administration, the above test compounds were given orally to the rats. Three hours later, animals were sacrificed and their stomachs were removed and opened along the greater curvature in order to examine the lesions macroscopically. Preliminary results showed that the protection afforded by CPE is about 53% in acidified ethanol and 67% in acetic acid-induced ulcer. In addition, CPE inhibited titratable acid 3.Serum lipid lowering effect of phytosterols and sesame lignan glucosides in
hamsters
Due to the prevalence of westernized diets, cardiovascular disease (CVD) has become a common chronic disease in Taiwan, and claims many lives each year. CVD mainly results from atherosclerosis. Hypercholesterolemia and oxidative stress are the major factors of proatherosclerosis. Phytosterols from deodorizer distillates in edible oil refining and sesame lignans extract from defatted sesame cake were respectively used to study their effects on lowering A high fat diet containing cholesterol was fed to weanling male hamsters to increase their cholesterolemic response. The hypercholesterolemic hamsters thus induced were then used for feeding test. A 5-week feeding study showed that hamsters given a diet containing 42mg/day of phytosterol (equal to 3g/day per human adult) had much lower total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and LDL-C/HDL-C of serum compared to the control group, which represents a reduction of 23.6% (p<0.05), 34.5% (p<0.05) and 12.5% (p<0.05) respectively. The hamsters given a diet containing 1.3mg/day of sesame lignan triglucoside and diglucoside extracts (equal to 80mg /day per human adult) respectively showed a 5.7% and 9.4% (p<0.05) reduction in TC. In addition, sesame lignan triglucoside extracts also showed a remarkable effect on the reduction (30.8%) in total triglyceride (TG) of serum. These results show that phytosterol and sesame lignan triglucoside and diglucoside are effective in lowering serum lipids of hamsters. 4. Effect of compounded oil on lowering serum lipids of hamsters
The type of dietary fat is closely related to the occurrence of cardiovascular disease (CVD). People who have hyperlipidemia should decrease the intake of dietary fat, saturated fatty acids and cholesterol. In the early 80s, scientists' studies showed that increased intake of monounsaturated fatty would have positive effect on plasma lipids. They found monounsaturated fatty acids possessed a lowering effect on serum cholesterol and lowdensity lipoprotein cholesterol (LDL-C) without raising serum triglyceride (TG). This research is aimed to evaluate the serum lipids lowering effect of the compounded oil developed by our Institute based on the act of "evaluation of health food on serum lipid" published by Department of Health, in Taiwan. A high fat diet containing cholesterol was fed to weanling male hamsters to increase their cholesterolemic response. These hyperlipidlemic hamsters thus induced were then used for feeding tests. An 8-week feeding study showed that serum TG levels were 28% lower for the group given compounded oils with a high content of monounsaturated fatty acids compared to the group given soybean oil (p<0.05), while the cholesterol, LDL-C and HDL-C levels showed no statistically significant difference between these two groups. These results indicated that the compounded oils with a high content of monounsaturated fatty acids were effective in lowering triglyceride III. New Technologies in Food Processing
1. A Pilot-Scale Study on the Processing Technologies of Multigrain Layer
The purpose of this research is to develop a pilot-scale method for production of multigrain layer noodle, which is made by sandwiching multigrain layer in between wheat noodle. The production method of multigrain layer noodle could be applied to the processing of wet, dry or instant noodle. It could create not only added value but also increase health benefits of the noodle products. The composition of the multigrain layer and its processing were studied by Response Surface Methodology. Results showed that the dry multigrain layer noodles prepared with the increment of other grains had lower breaking force and L value, but higher a value and required longer cooking time than those prepared by wheat flour alone. The cooked multigrain layer noodles also showed higher hardness and cooking loss with the increment of other grains. Also, the multigrain layer noodle showed higher breaking force, shorter cooking time and less cooking loss than those made with traditional method. A mechanism for sheeting of noodle dough with planetary rollers has been also developed in this study. The texture of the noodle produced by this mechanism was softer than the conventional noodle. The multigrain layer noodles obtained in this study possess excellent quality with the multigrain layer accounting for more than 43% of the total noodle. They are similar to the traditional noodle in size, shape, cooking time and texture 2. Preparation of multi-cereal pellets for microwave puffing
This study is aimed to set up a method for preparation of multi-cereal pellets for microwave puffing. Two methods, namely roller pressing and twin-screw extrusion were used for preparing the multi-cereal pellets. The composition of cereals, the processing conditions for forming pellets, the drying condition and the final moisture content of the pellets as well as the surface coating treatment were tested for their effects on the puffing performance of the dried pellets. It was found that the extrusion method could achieve better puffing performance of the pellet products. A combination of waxy rice flour, barley flour and buckwheat flour in a proper ratio along with the proper conditions of extrusion and drying could produce the multi-cereal pellets with good puffing by microwave heating. The pellets obtained in this study could be well puffed by high power microwave heating with a volume expansion of 550%. However, a proper surface coating of the pellets is required for low power (700 w) 3. Development of microwave assisted fry-drying system
A pilot plant of continuous microwave assisted fry-drying system was developed for instant noodles drying. This system used high temperature oil media to improve the heating uniformity and microwave energy to reduce oil uptake during frying. Major components of this system include: (1) a special designed metal cavity with microwave power sources and water load isolator, (2) a direct heated deep-frying pan, (3) exhaust pipes and microwave emission reducing apparatus, and (4) a control unit. Pilot test results showed that the microwave assisted fry-drying process operated at 7kW microwave energy output (0.75W/g power density) and 160℃ oil temperature could complete the drying of noodles within 50 seconds. It accounts for a 45% reduction in process time and 28% in oil uptake and causes no significant change of noodle quality as compared to the conventional oil frying process. According to the pilot test process parameters, a scale up design of a 28kW microwave frying system could be able to fulfill the commercial process capacity of 24,000 pieces noodle per 4. Process of microwave pasteurization for packaged food
A study of microwave heating pasteurization process for packaged shredded vegetables salad (cucumber and carrot) was carried out in this project. The results indicated that the process of 0.8W/g microwave density treatment for 5 minutes would raise the product temperature to about 50℃. This treatment resulted in a 3.4 log CFU/g reduction of the total plate count and a reduction of 3.0 log CFU/g of the coliform bacteria in cucumber samples, and reductions of 4.2 log CFU/g of the total plate count and 5.0 log CFU/g of the coliform bacteria in carrot samples. This microwave pasteurization process has found no significant changes of color and texture quality as compared to raw material. A scale up process design with a 20kW microwave power output is postulated to be capable of raising the product temperature to 60℃ in 7 minutes for packaged shredded vegetables to achieve proper pasteurization while maintaining fresh 5. Application of high intensity light pulses to the sterilization of fresh-cut fruits
The surface of fresh-cut fruits is susceptible to microbial contamination and enzymatic action and easily results in deterioration and rotting. Thermal processes could inactivated microbial and enzymatic reactions, but could also cause adverse changes of appearance, aroma, nutrient components and texture. Therefore this study is aimed to solve these problems by applying the high intensity light pulses to fresh-cut fruits, in combination with modified atmosphere package and refrigerated storage to extend their keeping quality and shelf-lives. Fresh-cut pineapple and guava treated with pulsed light irradiation and packaged in modified atmosphere were evaluated for occurrence of browning and rate of microbial change during storage with refrigeration. The results showed that the treated fresh-cut pineapple could be kept for 7 days, while the treated guava could be kept for 11 days, 4 days and 7 days longer comparing with those of the control groups respectively. 6. Studies on micro-encapsulation for oil extracted products of Chinese spices
Among various Chinese flavors or spices, the green onion, ginger and garlic have been widely used in preparation of many Chinese dishes. However, they are not stable and will easily become off-flavor or lose their characteristic flavor during storage and/or reheating of the products due to lipid oxidation and/or In order to work out this problem, the micro-encapsulation technique was studied for the oil extracted products from onion, ginger and garlic by means of spray-drying. The encapsulated products obtained in this study possessed good storage stability in color and flavor for more than 6 months at 25℃, comparing to less than 4 months for the un-encapsulated control products. These micro-encapsulated spices should play a significant role in promoting the IV. New Product Development and Quality Improvement
1. Development of Food Products for Senior Citizens (1)-Vegetables and Fruits
There are dazzling array of vegetable and fruit products in market, but most of them are designed for and targeted to the youth and children, few for senior people. Owing to physically metabolic declination, senior people need softer and more nutritious vegetable and fruit products in their diet. The purpose of this project is therefore to develop some nutritious yet convenient vegetable and fruit products such as puddings and powders for the senior consumers. It was found that papaya, mango and banana puddings which were made of fresh fruit purees, and tomato pudding which was made of canned tomato paste could meet the requirements for senior consumption in the respects of nutrition and texture. These puddings have a softer texture, higher mineral, dietary fiber and cellulose content than those currently available products made of fruit juices. The fruit powders of papaya, mango, banana and tomato could be successfully prepared by drying the fruit puree with the addition of suitable thickening agents, and followed by milling and screening. For vegetable powder, need of addition of thickening agents depends on whether the vegetables used for drying were crushed. Both fruit and vegetable powders could easily be dispersed in milk or rice congee and served as snack or breakfast. 2. Preparation of instant mint strips and studies on their properties
Mint containing l-menthol has a refreshing and cooling effect when ingested. It is generally used in confectioneries, oral hygiene, shaving products and etc. A thin mint strip product made by a blade coater was studied with maltodextrin as main matrix material to encapsulate mint. The soluble time, retention of l-menthol and storage stability of the strips were examined with different It was found that the better way to prepare the mint strips was as follows: prepare the mint solution consisting of mint flavor, mint and emulsifiers in proper ratio, then encapsulate the mint solution with maltodextrin matrix and finally form the strips by a blade coater. The mint strips thus prepared posses a nice oral-cool and nasal-cool sensation, short soluble time and good storage 3. Development of commercial production technologies for Chinese cuisines (II)
The purpose of this study is using modern food processing and preservation technologies to develop commercial production methods for high quality Chinese cuisines. These technologies include the choice of raw materials, pretreatment of raw materials, cooking and preservation methods. Last year we have established the commercial production methods for some stir-fried and roasted Chinese cuisines. This year we continue this study for steamed and fried Chinese cuisines. Four steamed (spicy tofu, steamed fish in fermented black bean sauce, chicken wings with spring onion and stewed spareribs) and five fried Chinese dishes (fried tofu, fried chicken, fried squid, fried oyster and fried lily corm and meat analog) have been studied and their commercial production technologies have been established. Some quality deterioration problems including texture toughening and consistency-weakening of soups have been also worked out in this study. The results of this study were expected to upgrade the processing technology and promote the added value of Chinese dishes. 4. Development of Soy-based fresh cheese
Due to its cholesterol-free nature and richness in physiologically functional ingredients, soymilk is a promising base to replace cow milk for production of cheese-like products. In this study we tried to use commercial lactic acid bacteria and beany flavor-free soymilk as major raw material to develop the processing technologies for soy-based fresh cheese. The fermentation and other processing conditions have been established in this study. The soy-based cheese-like product thus obtained has a pH of 4.4~4.6, an acidity of 0.75~0.8% (calculated as lactic acid) and a water content of 60~70% depending on pressing condition. A production yield of 32~45 (based on soy weight) could be achieved by this process. The soy-based fresh cheese obtained by this process could be stored in bulk for 2 weeks at 18℃ and 1 month at 4℃, and more than 3 months at 4℃ in vacuum package. The fresh cheese could even be further processed into cream cheese-like spreads by adding soy oil, salt, sugar and flavors. 5. Handbook of "The Fruit Storage in Taiwan" and "The Information of Fruits
and Vegetables Storage" Internet
Fresh fruits and vegetables are important agricultural produces in Taiwan. In addition to subtropical crops, tropical and temperate fruits and vegetables are also produced in Taiwan and available throughout the year. The access of Taiwan to WTO in 2001 has presented a great opportunity for the export of these produces, but on the other hand, Taiwan also faces severe competition of imported fruits and vegetables. Information on the storage and transportation requirements of fresh fruits and vegetables are therefore very important for farmers, transporters and marketing people. The handbook of " The Fruits Storage in Taiwan" was published (ISBN 957-9055-63-7) last year. The contents included "The basic knowledge of post-harvest handling and storage", "pre-cooling technology", "Quarantine demands in different countries", and "The storage of 42 popular fruits". Information on various aspects including Chinese name, English name, scientific name, alias, production season, the optimum storage temperature and humidity, chilling injury, storage life and photographs etc. are provided for each fruit. The Information of Fruits and Vegetables Storage internet has been established last year (www.tasc.firdi.org.tw: 8080) providing the storage information of more than forty locally produced fruits and eighty vegetables. V. Packaging Technology
1. Continuous Production Technology for Edible Films
The purpose of this study is to investigate the curing conditions for HPMC (H), HPMC + beeswax (L) and isolated soy protein + wheat gluten (P) during their film formation, by means of K118 continuous coating machine. These curing conditions may serve as the basis for manufacturing laminated films. It was found that L film would easily suffer from cracks during the curing process if the hot air speed were too high. Therefore, the curing conditions of L film must be adjusted on the basis of wet film thickness. The laminated films composed of H, L and P layers in different orders were prepared and tested for their heat-seal strength and O2- permeability. The results showed that only P layer could serve as sealing layer with a seal strength of 0.086 kgf ~ 0.185 kgf/15mm, and that these laminated films had an oxygen 2 permeability of less than 100 ml/m day. These laminated films could be applied to the packaging of seasoning ingredients 2. Extrusion technologies for vegetable casings making
The local vegetarian food industry in Taiwan has a tremendous demand for vegetable casings. The technologies for making edible casings with vegetable materials and extrusion process of blown films were developed in this study. The raw materials, composed mainly of soy protein and wheat starch, were extruded through a twin-screw extruder equipped with blown film dies. Extrusion processing parameters, additives, and blown film dies were studied for their influence on the properties of fabricated edible casings. All of these were found to affect the tensile strength of the edible casings thus prepared. An extrusion process with a capacity of 1.6 to 2.2×103 m/h for vegetable casings has been established in this study. The casings have a longitudinal tensile strength of 10 MPa and are suitable for wrapping food stuffs such as chicken rolls, rice and vegetable rolls as well as sushi and so on. However, they are not as good for vegetable sausage and ham owing to their poor tensile strength on the radial direction of extension. Further study is needed to improve it. Nevertheless, this process could be a promising alternative to the conventional drum drying process for yuba. The extrusion process developed in this study has been transferred to a company to prepare edible films in commercial scale for foodstuffs wrapping. 3. Development and Application of Antibacterial Film
Because of its relatively high inhibition to bacteria and low cost, zinc oxide was selected in this study as an antibacterial additive to replace the currently used but more expansive silver zeolite for making the antibacterial packaging film by means of a film-forming extruder. Our study showed that the film-forming temperature, the screw speed of the extruder, and the rotation speed of the cooling roller would have a great influence on the appearance and properties of the film thus obtained. In addition, the incorporation of proper dispersion agents would significantly contribute the performance of the antibacterial film. The antibacterial function of the film obtained in this study was examined by the logarithmic reduction values (LRV) as stated in JIS Z2801. For Escherichia coli, the LRV was 3.7, and 4.3 for Staphylococcus aureus. In packaging test, the antibacterial film could extend the storage life of the sliced ham by 6 days at 4℃ when compared with the corresponding non-antibacterial

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