Effects of alkaline,hydrogen peroxide-treated fibres on nutrient digestibility,blood sugar and lipid profile in rats

Three diets containing different sources of dietary fibre, wheat bran, faba bean testas and rice hulls, were tested to determine the effects of alkaline, hydrogen peroxide (AHP)-treated fibre at 10% substitution level of dextrose corn flour on apparent digestibility, faecal characteristics, and levels of plasma glucose and lipid profile in rats. A fourth non-fibrous diet was used as a control. The results showed that, although AHP treatment of fibres resulted in reduction of their weight after washing, it caused an increase in their water absorption and in their swollen volume when mixed with an excess of water (up to three fold) as in the case of wheat bran. Rats consuming diets containing dietary fibres showed a significant loss of body weight but no significant effects on heart weight or liver weight were found. Faeces of rats fed on dietary fibre diets showed an increase in weight and volume, which resulted in reduction of faecal density. The consumption of the treated fibre significantly reduced total cholesterol, plasma triglycerides and blood sugar; wheat bran was the most effective followed by rice hulls and faba bean testas. On the other hand, it effected an increase in the plasma content of high-density lipoprotein HDL-C but this increase was only significant in rats fed with wheat bran. Alkaline hydrogen peroxide-treated fibres showed a great improvement in their absorbency, making them equal to or even better than untreated fibre in lowering blood lipids and sugar levels, in addition to their excellent effect on the physiological function of the intestinal tract.     

Short-chain fatty acid content and pH in caecum of rats fed various sources of starch

Caecal pH and contents of short-chain fatty acids (SCFA) were registered in rats fed three potential sources of resistant starch (RS); raw pea starch, raw potato starch, and an RS-enriched preparation obtained from wheat starch by autoclaving and enzymatic incubation. Small intestinal digestibility and delivery of RS to the hind-gut in the case of raw starches were determined by analysis of faecal starch in animals treated with antibiotics to prevent hind-gut fermentation. RS content in the RS-enriched preparation was determined as total starch remaining in an enzymatic gravimetric dietary fibre residue. The fermentability of RS was estimated from the faecal recovery of starch in normal animals with intact hind-gut microflora. Approximately 35 g per 100 g and 32 g per 100 g were RS in the case of raw potato starch and the RS-enriched preparation, respectively, versus only 1 g per 100 g in the case of raw pea starch. The caecal pH decreased with all test diets, being most significant with raw potato starch. SCFA production and faecal bulking were negligible with raw pea starch, whereas both raw potato starch and the RS-enriched preparation significantly increased these parameters. The fermentability of RS in raw potato starch and the RS-enriched preparation was similar, or about 60–70%. If calculated on basis of fermented amount, RS in raw potato starch was more potent in generating SCFA (49 μmol g^?1) than in the RS-enriched preparation (19 μmol g^?1). RS in raw potato starch also displayed the highest faecal bulking capacity. In fact, the faecal dry weight increased more than expected merely from delivery of RS. The relative proportion in caecal contents of acetic-, propionic- and butyric acid was 70, 17 and 8%, respectively, with no significant differences between the three sources of RS.     

High-Hydroxypropylated Tapioca Starch Improves Insulin Resistance in Genetically Diabetic KKAy Mice

ABSTRACT:  The hypoglycemic and antidiabetic effect of hydroxypropyl tapioca starch (HPTS) with a varying degree of substitution (DS: 0.058, 0.091, and 0.180) was investigated in rats and KKAy mice, an animal model of type 2 diabetes. The positive incremental area under the curve (IAUC) for glucose significantly decreased as the DS of HPTS increased. The IAUC after intragastric intubation of the highest HPTS (HPTS-III, DS = 0.180) was 55% of the IAUC of tapioca starch (TS). After 28 d, fasting blood glucose and insulin concentrations were significantly lower in rats fed HPTS-III (50 g/kg diet) than in those fed TS ( P < 0.05). In KKAy mice fed HPTS-III (50 or 100 g/kg diet) for 33 d, as compared with TS, there was a delay in the detection of glucose in urine and also a decreased incidence of finding glucose in urine on days 7, 21, and 28; in addition, the AUCs for glucose in the oral glucose tolerance test on days 14 and 28 were significantly lower ( P < 0.05 and P < 0.05, respectively). The plasma adiponectin concentration and the quantitative insulin sensitivity check index (QUICKI) were significantly higher in mice fed HPTS-III than in those fed TS ( P < 0.01), whereas the homeostasis model assessment of insulin resistance (HOMA-IR) was lower ( P < 0.01). Energy intake was significantly lower in mice fed HPTS-III than in those fed TS. These findings show that HPTS with a high DS resists digestion by α-amylase and improves insulin resistance in KKAy mice by decreasing energy intake. However, the potential mechanism by which HPTS-III decreases energy intake is unclear at present.     

Rice Protein Isolates Produced by the Two Different Methods Lower Serum Cholesterol Concentration in Rats Compared with Casein

Highly purified rice protein isolates (RPI) were prepared by an alkaline extraction–acid precipitation method (E-RPI) and by an α-amylase treatment to remove starch (T-RPI). Biological values of these RPI were significantly lower than that of casein. Serum cholesterol concentrations were compared among groups of rats fed (per kg diet) 200, 300 or 400 g E-RPI, 400 g T-RPI, 250 or 400 g casein kg⁻¹ or 400 g soya bean protein isolate (SPI). With all the diets containing 400 g protein kg⁻¹ diet, growth rates of rats were the same. At this level, E-RPI, T-RPI and SPI diets produced significantly lower serum cholesterol concentrations than the casein diet. Faecal bile acid plus neutral steroid excre-tion was significantly higher in rats fed the 400 g kg⁻¹ T-RPI or 400 g kg⁻¹ SPIdiets compared with rats fed the 400 g kg⁻¹ casein diet. On the other hand, the 400 g kg⁻¹ E-RPI diet did not increase steroid excretion. Plasma cholesterol concentrations in rats fed diets with amino acid mixtures simulating SPI and E-RPI were also significantly lower than that of rats fed the diet with an amino acid mixture simulating casein even though the faecal excretions of total bile acids were the same amongst groups. These results support the view that RPI are hypocholesterolaemic relative to casein and at least the hypocholesterolaemic effects of E-RPI would be independent of interruption of the enterohepatic circulation of endogenous steroids.     

High apparent ileal digestibility of amino acids in raw and germinated faba bean (Vicia faba)‐ and chickpea (Cicer arietinum)‐based diets for rats

The effects of germinated faba bean (Vicia faba minor var Alameda)‐ and chickpea (Cicer arietinum kabuli var Athenas)‐based diets on performance, N utilisation, amino acid ileal digestibility and plasma concentrations were studied in growing male Wistar rats. Raw and germinated faba bean and chickpea seed meals were incorporated in essential amino acid‐supplemented and energy‐equalised diets as the only sources of protein. A lactalbumin‐based diet equalised in protein (100 g kg^?1) and digestible energy (15.5 kJ g^?1) with the test diets was used as control. Weight gains, gain/feed ratios, N retention and NPU values of animals fed raw or germinated legumes were lower than those of rats given the control (lactalbumin) diet, while faecal dry weights were higher. However, N retention and NPU values of rats fed germinated faba bean diets were higher and faecal dry weights lower than those of animals fed non‐germinated faba bean diets. Liver and thymus fresh and dry relative weights were lower than controls for all legume diets, whilst small intestine, caecum and colon relative weights were higher than controls for non‐germinated faba beans and chickpeas either germinated or not. Caecum and colon fresh and dry relative weights of rats fed germinated faba bean seeds were lower than those of rats fed non‐germinated faba beans and not different from controls. Except for aspartic acid and proline in rats fed raw faba bean diets, apparent ileal digestibilities of amino acids were not different or higher in rats fed legume diets as compared with controls. Except for arginine, apparent ileal amino acid digestibility was higher for germinated than for non‐germinated faba bean seeds. The amounts of glycine, arginine and ornithine in plasma significantly increased whilst those of threonine, alanine, leucine and lysine decreased with respect to controls in faba bean‐ or chickpea‐fed rats, either germinated or not. We conclude that (a) germination of faba bean seeds gave rise to a significant (P < 0.01) but limited improvement in performance, N retention and apparent ileal digestibilities of some amino acids in growing rats compared with non‐germinated seeds, while there was no detectable effect in the case of germinated chickpea seeds, and (b) the apparent ileal amino acid digestibility of essential amino acid‐supplemented diets based on faba bean or chickpea meals, either germinated or not, is similar or even higher than controls. © 2002 Society of Chemical Industry     

Physicochemical properties and emulsification properties of maize starch modified by hydrochloric,phosphoric and tartaric acid

Native maize starch (NS) dispersions treated with hydrochloric (HA; 1M, 2M), phosphoric (PA; 1M, 2M) and tartaric acid (TA; 0.67M, 1.33M) were investigated in terms of their morphological, structural and physicochemical properties, including emulsification capacity. The molecular weight of starch was affected by both factors (acid type and concentration). The mean molecular weight (Mw) was decreased by 89% and 11% after treatment with HA (1M) and PA (1M), respectively. TA-treated starch resulted into three distinct size distributions, one of which showed larger Mw as compared to the NS. Dynamic light scattering measurements revealed that the modified starches in aqueous environment were spread in at least two distributions, one of them showing particle sizes higher than 200 nm, whereas the other lower than 200 nm. Clarity of treated starch pastes decreased in the following order: HA > TA > PA > NS. Generally, O/W emulsification and stability properties deteriorated with starch modification. ΤΑ yielded the most stable emulsion among the modified starches.     

Influence of Legume Starches on Protein Utilization and Availability of Lysine and Methionine to Albino Rats

Starch was extracted from red gram (Cajanus cajan), Bengal gram (Cicer arietinum), black gram (Phaseolus mungo), and green gram (Phaseolus aureus). The effect of these starches on the utilization of casein was tested in albino rats using PPER, digestibility co-efficient, biological value, and net protein utilization as parameters. Lysine and methionine available to rats was also determined. The phaseolus starches promoted growth similar to corn starch but the growth of rats fed on red gram and Bengal gram starch was significantly less (P < 0.05). The digestibility coefficient of casein was reduced significantly when supplemented with red gram starch compared to the other legume starches. No difference was noticed in the biological value of casein supplemented with the four legume starches. However the net protein utilization of casein was significantly (P < 0.05) higher when supplemented with black gram starch compared to other legume starches. Availability of lysine to rats fed with phaseolus starches was significantly higher than for rats fed with other legume starches.     

Short‐term feeding of fermentable dietary fibres influences the gut microbiota composition and metabolic activity in rats

This study investigated the effects of dietary fibres on gut bacterial abundance and metabolic activity in rats fed short‐term. Faecal samples from rats fed for 7 days showed differences in the effects of dietary fibres on gut bacterial populations. Broccoli fibre, inulin, potato fibre and potato resistant starch significantly increased the faecal Bacteroides‐Prevotella‐Porphyromonas group compared with cellulose. Growth of pathogenic bacteria such as Clostridium perfringens, Escherichia coli and Enterococcus spp. was decreased significantly in rats fed barley β‐glucan, citrus pectin, inulin and broccoli fibre diets. An increase in Bifidobacterium spp. and butyric acid levels, the so‐called bifidogenic and butyrogenic effects, was observed in rats fed inulin and potato fibre diets. Organic acid concentrations and polysaccharide contents in the rat faeces confirm the fermentability of dietary fibres in the gut. This study demonstrates the positive effects of plant‐sourced dietary fibres on gut microbiota composition and metabolic activity.     

Organs relative weight and plasma amino acid concentrations in rats fed diets based on whole legume (faba bean,lupin, chickpea,defatted soybean) seed meals or their fractions

The effects on organ relative weights (g per 100 g bw) and plasma amino acid concentrations of diets based in legume (faba bean (Vicia faba), lupin (Lupinus angustifolius), chickpea (Cicer arietinum) and soybean (Glycine max)) seed meals as the only source of protein were studied with growing rats using lactalbumin or casein as controls. Also, legume seed meal extracted globulins were included in control diets replacing lactalbumin to produce legume globulin‐based diets, and legume residue fractions, containing most of the starch and/or insoluble fibre (NSP+lignin) from the seed meals, were included in control diets to reach the same amounts present in whole legume seed meal diets. All experimental diets were formulated to contain the same amounts of protein (100 g kg⁻¹) and energy (15.5 kJ g⁻¹), and were supplemented with essential amino acids. Compared with lactalbumin, higher relative weights of gastrointestinal sections were determined in rats fed legume seed meals or their corresponding residue fractions. On the contrary, spleen relative weight was lower in rats fed diets containing lupin, chickpea or soybean meals or extracted globulins, while residue fractions had no effect on it. Thymus relative weight was also lower in rats fed whole chickpea seed meal or any of the extracted legume globulins. Except for chickpea meal, animals fed legume‐ or legume protein‐based diets had lower liver relative weights than controls. Lower proportions (mg g⁻¹ tissue) of glycogen, and lower total protein and RNA, were also determined in the livers of rats fed lupin seed meal. Free plasma concentrations (mM litre ⁻¹) of glycine, histidine and arginine were higher, and threonine, leucine and lysine were lower, in rats fed diets based in all legume seed meals of their respective globulin proteins. The possible reasons and implications of these results are discussed. © 1999 Society of Chemical Industry     

Hydroxypropyl-Distarch Phosphate from Potato Starch Increases Fecal Output, but Does Not Reduce Zinc, Iron, Calcium, and Magnesium Absorption in Rats

The physiological effects of hydroxypropyl‐distarch phosphate (HDP) were examined in rats. Male rats were fed a fiber‐free purified diet containing gelatinized potato starch (PS, 50 g/kg diet) that was not modified chemically or gelatinized, chemically modified potato starch (CMS, 50 g/kg diet) for 21 d. PS was used as the control. Six kinds of gelatinized HDP from potato with 2 different degrees of hydroxypropylation and 3 different degrees of cross‐linking were used as CMS. The wet weight and moisture of the fecal output of the rats fed highly hydroxypropylated HDP was 70% and 30% greater, respectively, than that in the control rats. The weights of the cecal wall and content of the rats fed highly hydroxypropylated HDP were 15% and 30% higher, respectively, than those of the control rats. The apparent absorption of Mg was 15% higher in the rats fed highly hydroxypropylated HDP than in the control rats. On the other hand, the apparent absorptions of Ca, Zn, and Fe were not affected by the diet. Cross‐linking did not influence the above‐mentioned physiological effects of HDP. Fecal excretion of bile acids and the plasma cholesterol concentration were not affected by the diet. These results show that the physiological effects of HDP depend on the hydroxypropylation but not the cross‐linking.     

Comparative effects of slowly digestible and resistant starch from rice in high-fat diet-induced obese mice

Food Science and Biotechnology - The effects of optimized slowly digestible starch (SDS) and resistant starch (RS) from rice starch on weight gain and lipid metabolism in mice (C57BL/6J mice) fed a...     

Effect of Various Processing Methods on the Physical Properties of Cooked Rice and on in vitro Starch Hydrolysis and Blood Glucose Response in Rats

The effects of various cooking methods on the physical and structural properties cooked rice, on the in vitro hydrolysis of the contained starch and on blood glucose response in rats were investigated. At optimum cooking state, a larger filamentous network was formed and most of the starch granules were fragmented, furthermore the samples heated by microwave and electric cooker showed a more compact structure compared to those treated in an autoclave or stone pot. The highest degree of gelatinization (DG) was observed in the sample treated in an autoclave (75.2%), followed by stone pot (71.1%), electric cooker (66.9%) and microwave oven (64.6%). The highest firmness (3.49 N) was observed in cooked rice heated by microwaves and no significant differences (p > 0.05) were found between the other samples. All cooked rice samples showed increased pasting temperatures and decreased peak viscosity compared to those of raw rice flour. The starch hydrolysis rates and their kinetic constants of cooked rice samples increased with increase in DG, and relatively higher values were observed in samples treated in the autoclave and stone pot. There was a significant difference in the blood glucose content depending on cooking methods, and the highest glucose level was observed in the sample heated by autoclaving.     

Effect of Heat‐Moisture Treatment on Structural and Thermal Properties of Rice Starches Differing in Amylose Content

Starches from glutinous rice (1.4% amylose), Jasmine rice (15.0% amylose) and Chiang rice (20.2% amylose) were exposed to heat‐moisture treatment (HMT) at 100 °C for 16 h and at different moisture levels (18, 21, 24 and 27%). The effect of heat‐moisture treatment on structural and thermal properties of these three rice starches was investigated. The HMT did not change the size, shape and surface characteristics of rice starch granules. The A‐type crystalline pattern of rice starches remained unchanged after HMT. The relative crystallinity (RC) and the ratio of short‐range molecular order to amorphous (RSA) of heat‐moisture treated glutinous and Jasmine rice starches decreased with increasing moisture level of the treatments. In contrast, the RC of the treated Chiang rice starch remained practically unchanged. A peak of crystalline V‐amylose‐lipid complexes was clearly presented in all treated Chiang rice starches. The peak became progressively stronger with increasing moisture level of the treatment. Differential scanning calorimetry (DSC) of all treated rice starches showed a shift of the gelatinization temperature to higher values. Increasing moisture level of the treatments increased the onset gelatinization temperature (T_o) but decreased the gelatinization enthalpy (ΔH) of rice starches. A broad gelatinization temperature range (T_c‐T_o) with a biphasic endotherm was found for all treated Chiang rice starches and Jasmine rice starch after HMT₂₇ (HMT at 27% moisture level). Additionally the (T_c‐T_o) of treated Chiang rice starches increased linearly with increasing moisture level of the treatments.     

Starch Granule-Bound Proteins and Polypeptides: The Influence of the waxy Mutations

Proteins are found as integral components of starch granule structure. The starch granule-bound proteins from the endosperm of nonmutant (normal) and waxy (glutinous) cereals were extracted and subsequently separated by electrophoresis on denaturing SDS-polyacrylamide gels. The silver stained gels revealed that for cereals the waxy protein (starch granule-bound starch synthase) was approximately 60 kD. The cereals containing the waxy mutation do not show this protein. Compared to the nonmutant genotypes of other cereals, the waxy protein of barley, Hordeum vulgare is greatly diminished. Based on this observation, there may be reason to suspect that starch synthesis in barley varies from that of other cereals. There are minor homologous proteins among the cereals studied, including, maize, teosinte, rice, millet, sorghum, and barley. Starch granules from all cereal genotypes studied exhibited a minor protein at 68 kD. Most (81%) genotypes showed a 65 kD protein, which may correspond to a minor isozyme of starch granule-bound starch synthase. Minor proteins occurred at 70 kD and 72 kD in 71% and 57% of the genotypes studied, respectively. The minor proteins could be isozymes of starch granule-bound starch synthase or the proposed granule-bound forms of branching enzyme and oligosaccharide synthase.     

Nature of Crystallinity in Native and Acid Modified Starches

Crystalline characteristics of natural and acid modified starches (cereals, millets, pulses, root, and tuber) were examined by X-ray diffraction studies. The (hkl) planes were identified using A-, B- and C- type starch cell parameters. The size of crystallite along the direction [hkl] was calculated for all the reflections in the starches. Smallest crystallites (35 to 56 Å) are observed for the reflections at (2θ) 11.2 to 11.5° corresponding to (111) reflection plane, waxy rice showing the lowest value of 35 Å. Largest crystallite size of the order 200 Å is observed at 2θ 20.0 to 20.4° corresponding to (032) reflection plane with finger millet giving the highest value in the order of 289 Å. Acid modification leads to minor changes in ‘d' spacing but crystallite size changes quite considerably. It increases in some, decreases in others, and remains unchanged in few cases. There was no uniform pattern observed either with respect to acid used, source of starch or the peak at which the changes occur. In finger millet starch, crystallite size becomes homogeneous upon acid treatment.     

Studies on digestibility of selected legume carbohydrates and its impact on the ph of the gastrointestinal tract in rats

A study on the digestibility of legume carbohydrates in unprocessed and processed grain and also in the starch isolated from the grain was carried out by in vitro and in vivo methods. The legumes selected were red gram (Cajanus cajan cv. Hyd. 3A), Bengal gram (Cicer arietinum cv. BEG 482), black gram (Phaseolus mungo cv. T9) and green gram (Phaseolus aureus cv. PS 16). The processes tested were boiling, pressure cooking, roasting, germination, fermentation and parching. The digestibility in vitro was assessed on the basis of maltose released after amylolysis and digestibility in vivo was assessed on the basis of carbohydrate intake and excretion. Digestibilities of the Phaseolus varieties were superior to red gram and Bengal gram. Roasting did not improve the digestibility of any legume as much as boiling and pressure cooking. The digestibility of fermented and germinated legumes was not much higher than the legumes processed by other methods. The increasing order of digestibility in vivo was red gram < Bengal gram < black gram and < green gram. Significant differences were noticed in the digestibility in vivo of moist and dry heat-treated legumes, and between Phaseolus starches and red gram and Bengal gram starch. The pH values of stomach, duodenum and small intestine contents of rats fed legume diets was greater than the pH values at similar sites in rats fed casein protein, whereas the pH values in the caecum of rats fed on legume diets was acidic and that of casein-fed rats was neutral. Caecum weight of rats fed on red gram and Bengal gram diets was significantly higher (P<0.05) than black gram- and green gram-fed groups.     

Plant starches and oils. Their influence on digestion in rats

The purpose of the present study was to determine the interaction effect of starch and fat of such products over blood parameters (cholesterol, triglycerides), and to evaluate starch and fat digestibility. Experiments were carried out in eight groups of Sprague-Dawley rats that were under the following diets: four of the groups were fed with a mix of 14% palm oil and 58% of each one of the starches (rice, corn, manioc and green plantain); the other four groups were fed a mix of 14% of corn oil and 58% of each one of the same starches under study. No significant differences were found in liver weight or fat digestibility among the groups of study. Significant differences were found on the starches digestibility, the green plantain starch being the one with the lowest digestibility (83–97%). The statistical differences showed an interaction between the starch and oil that affects the starch present in faeces and the starch digestibility. The evaluation of the blood parameters (cholesterol and triglycerides) showed significant differences when different starches were fed, but no so, when oils were changed. Animals that were fed manioc starch showed a higher concentration of cholesterol and triglycerides (244–150 mg dl⁻¹), while animals that ingested green plantain starch showed the lowest concentration (93–150 mg dl⁻¹). Our results suggest that the levels of cholesterol in rats was probably influenced by the digestibility of the starches present on the diet. The statistical analysis showed a high interaction starch vs oil over plasmatic triglycerides concentration. The green plantain starch has the same effect as some of the resistant starches. © 1998 SCI.     

Comparative Effects of Acetylated and Unmodified High‐amylose Maize Starch in Rats

Acetylated, propionylated or butyrylated starches raise the large bowel pools of these short chain fatty acids (SCFA) in rats but their resistant starch (RS) content in vivo is unknown. This content was determined for acetylated starch (Starch A, DS = 0.18) in colectomised rats and compared to a standard maize (control) or high‐amylose (HAMS) maize starch. Digestibilities were 99.8% (control), 47.5% (Starch A) and 58% (HAMS). The effects of Starch A and HAMS were compared also in intact rats, that were fed a fibre‐free diet in which either 200 g/kg of HAMS or 100, 200 or 300 g of Starch A/kg was substituted for the standard maize starch. Caecal SCFA pools were larger in rats fed either RS with the greatest increase being in acetate in rats fed Starch A. Other acids (succinate and formate) appeared with increasing incorporation of RS. However, when the experiment was performed with a commercial diet, feeding Starch A or HAMS did not lead to any great increase in these other acids but SCFA pools expanded. The greatest increase in acetate was in rats fed Starch A. This suggests that other factors were necessary for optimal RS fermentation but not for release of acetate from Starch A. Comparison of the effects of Starch A and HAMS on SCFA suggests that the former was at least 100% more effective than HAMS at equivalent dietary intakes, despite similarities in RS content. Incubation of Starch A with caecal bacterial enzymes confirmed that release of acetate was relatively slow, indicating a capacity of this modified starch for sustained SCFA delivery in vivo.     

Chemical and Physical Characterisation of Grain Tef [Eragrostis tef (Zucc.) Trotter] Starch Granule Composition

Chemical and physical properties of starch granules isolated from five grain tef (Eragrostis tef) varieties were characterised and compared with those of maize starch. Endogenous starch lipids extracted with hot water‐saturated n‐butanol and total starch lipids extracted with n‐hexane after HCl hydrolysis were 7.8 mg/g (mean) and 8.9 mg/g (mean), respectively, slightly lower than in the maize starch granules. The starch phosphorus content (0.65 mg/g) was higher than that of maize starch but virtually the same as reported for rice starch. The starch granule‐swelling factor was lower than that of maize starch and extent of amylose leaching was higher. The starch X‐ray diffraction pattern was characteristic of A type starch with a mean crystallinity of 37%, apparently lower than the crystallinity of maize starch and more similar to that reported for rice and sorghum starches. The starch DSC gelatinisation temperature was high, like for other tropical cereals; T_o, T_p, T_c and ΔH were in the range 63.8—65.4, 70.2—71.3, 81.3—81.5 °C and 2.28—7.22 J/g, respectively. The lower swelling, apparently lower percentage crystallinity and lower DSC gelatinisation endotherms than maize starch suggest that the proportion of long amylopectin A chains in tef starch is smaller than in maize starch.     

转人乳铁蛋白基因大米的慢性毒性研究

目的 观察转人乳铁蛋白(hLF)基因大米是否具有慢性毒性作用.方法 初断乳的180只SD大鼠按性别、体重随机分为3组:转基因hLF基因大米组、亲本大米对照组和AIN-93对照组,分别饲喂相应饲料12个月.观察大鼠的体重、进食量、血常规、血生化情况,实验末期处死动物,称量脏器重量并对脏器进行病理学检查.结果 转hLF基因大米组血常规(LYM％、GRN％)、血生化(ALT、AST、GLU)在个别时间点上与亲本对照组或AIN-93对照组存在显著差异(P＜0.05);其他观察指标与两个对照组均无显著差异.结论 现有实验结果不能证实转hLF基因大米对大鼠有慢性毒性作用.