Chi-Fai Chau

Functional properties of flours prepared from three Chinese indigenous legume seeds

The functional properties of Phaseolus angularis, Phaseolus calcaratus and Dolichos lablab flours were investigated and compared with those of soybean flour. The minimum nitrogen solubilities of P. angularis and P. calcaratus flours were at pH 5 while that of D. lablab flour was at pH 4. Compared with soybean flour, P. angularis, P calcaratus and D. lablab flours exhibited lower foam capacities, water- and oil-holding capacities, but higher gelation capacities. The emulsifying activities and emulsion stabilities of all legume flours tested were pH-dependent with minimum values at pH 4. Their emulsion stabilities were greater than 80.2% from pH 2 to 10, except at pH 4. Foam capacities and stabilities were also pH-dependent, highest foam stabilities being at pH 4.

DNA methods for identification of Chinese medicinal materials

As adulterated and substituted Chinese medicinal materials are common in the market, therapeutic effectiveness of such materials cannot be guaranteed. Identification at species-, strain- and locality-levels, therefore, is required for quality assurance/control of Chinese medicine. This review provides an informative introduction to DNA methods for authentication of Chinese medicinal materials. Technical features and examples of the methods based on sequencing, hybridization and polymerase chain reaction (PCR) are described and their suitability for different identification objectives is discussed.

Effects of cooking on content of amino acids and antinutrients in three Chinese indigenous legume seeds

The effects of domestic cooking on the content of amino acids and antinutrients of Phaseolus angularis, Phaseolus calcaratus and Dolichos lablab seeds were evaluated. Heat treatment (30 min) caused significant declines (P<0·05) in the apparent recovery of most of the essential amino acids except leucine and phenylalanine for P angularis, and except phenylalanine for P calcaratus. Cooking D lablab seeds (60 min) also resulted in a significant reduction (P<0·05) in the apparent recovery of all the essential amino acids except leucine, histidine, lysine and threonine. Increased cooking time for P angularis (60 min), P calcaratus (60 min) and D lablab (120 min) led to a lower apparent recovery of methionine (28·9–31·6%) and cystine (17·1–19·3%). Even with increased cooking times, the total essential amino acid levels in all three cooked seeds remained higher than that of the FAO/WHO requirement, except for methionine and cystine. Cooking (60 min) was found to be effective in reducing the tannin contents of P angularis, P calcaratus and D lablab seeds by 70·6, 64·6 and 74·6%, respectively. Upon cooking, phytate and trypsin inhibitory activity in different seeds were also reduced to different extents depending on the cooking times. ©1997 SCI

Inhibitory effects of Ganoderma lucidum on tumorigenesis and metastasis of human hepatoma cells in cells and animal models.

Metastasis is considered to be the major cause of death in patients with cancers, and hepatocellular carcinoma (HCC) is a highly metastatic cancer. Ganoderma lucidum , a well-known mushroom with various biological effects, is a functional food known to contain lucidenic acid. The objectives of this study were to investigate the anti-invasion effect of a lucidenic acid-rich G. lucidum extract (GLE) on human hepatoma HepG2 cells as well as the antiproliferative and antimetastatic effects of GLE in human hepatoma cells implanted into ICR-nu/nu mice. Phorbol-12-myristate-13-acetate (PMA)-induced invasion and matrix metalloproteinase (MMP)-9 expression levels of HepG2 cells were reduced by GLE treatment in a dose-dependent manner. The inhibitory effects of GLE on MMP-9 expression proceeded by inhibiting the phosphorylation of extracellular signal-regulated kinase (ERK1/2) and protein kinase B in the cytosol as well as reducing activator protein-1 and nuclear factor-kappa B levels in the nucleus of HepG2 cells. In a human tumor xenograft model, a dose-response inhibition was observed in the average size, volume, and weight of tumors upon oral administration of GLE. The number of metastatic tumor-bearing mice, the number of affected organs, and the number of tumor foci as well as the MMP-2 and -9 activities in serum of mice were also significantly suppressed by oral administration of GLE. These results suggest that the lucidenic acid-rich GLE could serve as a chemopreventive agent for the tumorigenesis and metastasis of highly invasive hepatoma cells.

Effects of Water-Soluble Carbohydrate Concentrate from Chinese Jujube on Different Intestinal and Fecal Indices

This study was to investigate the effects of water-soluble carbohydrate concentrate (WSCC) prepared from Chinese jujube ( Zizyphus jujuba) on different intestinal and fecal indices in a hamster model. WSCC contained carbohydrates (771 g kg(-1) of WSCC) including glucose, fructose, pectin polysaccharide, and hemicellulose. The administration of WSCC (5.0 and 15 g kg(-1) of diet) effectively ( P<0.05) shortened gastrointestinal transit time (by 34.2-57.3%), reduced cecal ammonia (by 58.1-60.3%), elevated total short-chain fatty acid concentrations in cecum (3-4-fold), increased fecal moisture (147-170%), reduced daily fecal ammonia output (by 31.9-75.8%), and decreased the activities of beta-D-glucuronidase (by 73.0-73.8%), beta-D-glucosidase (by 58.2-85.7%), mucinase (by 46.2-72.6%), and urease (by 31.9-48.7%) in feces. This study suggested that adequate consumption of jujube WSCC (at least 5.0 g kg(-1) of diet or 40 mg day(-1)) might exert favorable effects on improving the gastrointestinal milieu and reducing the exposure of intestinal mucosa to toxic ammonia and other detrimental compounds.

EFFECTS OF THE PHYSICO-CHEMICAL PROPERTIES OF THREE LEGUME FIBERS ON CHOLESTEROL ABSORPTION IN HAMSTERS

Abstract The effects of the insoluble dietary fibers (IDFs) prepared from Phaseolus angularis, Phaseolus calcaratus , and Dolichos lablab seeds relative to cellulose as control on cholesterol absorption in hamsters were studied. Test diets which contained 5% of cellulose and the three legume IDFs as the sole source of dietary fiber were fed to male Golden Syrian hamsters for 30 days. Compared to the control diet, all three legume IDF diets significantly ( P P. calcaratus IDF diet significantly reduced ( P D. lablab IDF diet diet led to a significantly ( P P r = −0.99, 1.00, and 0.95, respectively, P

Particle size reduction effectively enhances the cholesterol-lowering activities of carrot insoluble fiber and cellulose.

This study investigated and compared the effects of particle size reduction on the cholesterol-lowering activities of carrot insoluble fiber-rich fraction (IFF) and plant cellulose. Our results demonstrated that micronization treatment effectively pulverized the particle sizes of these insoluble fibers to different microsizes. Feeding the micronized insoluble fibers, particularly the micronized carrot IFF, significantly (p < 0.05) improved their abilities in lowering the concentrations of serum triglyceride (18.6-20.0%), serum total cholesterol (15.5-19.5%), and liver lipids (16.7-20.3%) to different extents by means of enhancing (p < 0.05) the excretion of lipids (124-131%), cholesterol (120-135%), and bile acids (130-141%) in feces. These results suggested that particle size was one of the crucial factors in affecting the characteristics and physiological functions of insoluble fibers. Therefore, particle size reduction by micronization might offer the industry an opportunity to improve the physiological functions of insoluble fibers, particularly the carrot IFF, in health food applications.

Investigation on the lipid- and cholesterol-lowering abilities of biocellulose.

The present study investigated and compared the physicochemical properties as well as the hypolipidemic and hypocholesterolemic effects between plant cellulose and biocellulose. Biocellulose had higher water-holding and cation-exchange capacities than plant cellulose ( approximately 2- and 6-fold, respectively). The results showed that the administration of plant cellulose and biocellulose to hamsters effectively ( P < 0.05) decreased the concentrations of serum triglyceride (by 13.9-55.5%), serum total cholesterol (by 17.4-27.9%), serum low-density lipoprotein cholesterol (by 41.9-47.9%), liver total lipids (by 6.4-10.3%), and liver cholesterol (by 11.8-16.3%). Feeding plant cellulose and biocellulose also enhanced the excretion of total lipids (144-182%), cholesterol (136-203%), and bile acids (259-479%) in feces. The efficacy of biocellulose in lowering serum lipids and cholesterol in hamsters was significantly higher than that of plant cellulose. These results suggested that biocellulose could be a promising low-calorie bulking ingredient for the development of novel fiber-rich functional foods of different forms such as powder, gelatinous, or shred forms.

Improvement of the hypocholesterolemic activities of two common fruit fibers by micronization processing.

This study investigated and compared the potential hypocholesterolemic activities of different insoluble fibers (IFs) prepared from carambola and orange pomace with or without micronization processing. After micronization, the cation-exchange and water-holding capacities of these pectic polysaccharide-rich IFs were effectively increased (from 140 to 180% and from 260 to 290%, respectively). The abilities of these microsized fruit IFs to lower the concentrations of serum triglyceride (by 15.6-17.8%) and serum total cholesterol (by 15.7-17.0%) were significantly (p < 0.05) improved, possibly by means of enhancing the excretion of cholesterol (123-126%) and bile acids (129-133%) in feces. Fecal moisture content was also increased (127-131%) by the consumption of microsized IFs. These results demonstrated that particle size is an important factor in affecting the characteristics and physiological functions of insoluble fibers. The approach of micronization processing might offer the industry an opportunity to improve the physiological functions of food fibers in fiber-rich functional food applications.

Micronization Increases Vitamin E Carrying and Releasing Abilities of Insoluble Fiber

This study was to investigate the effects of micronization on vitamin-carrying capacity and slow-release ability of carambola (starfruit) insoluble fiber (IF) and cellulose using in vitro and in vivomodels. Upon micronization, carambola IF (8.1 microm) underwent structural changes to expose more functional groups in the fiber matrix and to exhibit higher oil-holding capacity ( approximately 20.4-fold). Micronized fibers in forms of fiber-vitamin composites, particularly the micronized carambola IF-vitamin composite, were capable of carrying vitamin E (alpha-tocopherol) up to 9.6-fold over their unmicronized forms and releasing nutrient gradually. Animal studies demonstrated that the adminstration of micronized carambola IF-vitamin composite could maintain the plasma vitamin E of rats at relatively higher levels (2.1-3.6-fold of the initial values) for at least 5 h. The results suggested that micronized fibers, particularly the micronized carambola IF, could be exploited as potential nutrient carriers in food applications and also be used to produce slow-release formulations.