CCD-二极管阵列分光光度法同时测定食品中的维生素B1和维生素B2

为建立一种同时测定食品中维生素B1和维生素B2的简单快速的方法，在氢氧化钠和碳酸氢钠混合溶液缓冲介质中，对氨基苯磺酸重氮盐与维生素B。发生偶氮反应，维生素B2不发生反应，采用电感耦合二极管阵列检测装置进行检测，用偏最小二乘法解析重叠光谱，从而实现了对食品中维生素B1、维生素B2的同时测定。方法的线性范围维生素B。和维生素B2分别为0～0.050mg/mL和0～0．10mg／mL；检出限分别为0．0072mg／mL和0．0085mg／mL。平均加标回收率维生素B1为87．3％～105．4％，维生素B2为90．0％～104．9％；相对标准偏差维生素B1为3．6％～9．1％，维生素B2为4．7～8．0％。该方法简单、快速、测定干扰小，结果与国家标准测定方法的差异无显性。     

The effect of germination process on the superoxide dismutase-like activity and thiamine,riboflavin and mineral contents of rapeseeds

Seeds of double low oilseed rape variety Mango (Brassica napus, var. oleifera) were subjected to a 7-day germination at 25 °C and 95% moisture content in darkness in a conditioning cabinet. The effects of the germination process on the superoxide dismutase-like activity (SOD-like activity), thiamine (vitamin B₁) and riboflavin (vitamin B₂) and minerals, such as Ca, Mg, Cu, Fe and Mn, were studied. Correlations between individual mineral contents, vitamin B₁ and B₂ contents, and the ability of phosphate buffered saline (PBS) extracts from germinated rapeseed to scavenge superoxide anion radicals in vitro were also investigated. SOD-like activity showed a gradual increase after the second day of germination, reaching a maximum level on the sixth day, and remained almost constant up to the end of the germination period. During germination, thiamine underwent a progressive decrease up to the sixth day, reaching a constant level between the sixth and the seventh day. In contrast, riboflavin content increased throughout the germination period up to the fifth day, and after that a constant level was observed. Levels of Ca and Mg were almost constant up to the fourth day and after that an increase of these minerals was observed. Cu and Mn increased during the germination process, and retentions of 33% and 22%, respectively, were observed at the end of germination. Fe content dropped after 1 day of germination and from there onward it started to increase gradually and an 18% retention was observed in 7-day germinated seeds. Positive correlations between SOD-like activity and riboflavin (r = 0.87), Cu (r = 0.74) and Mn (r = 0.87) were found during rapeseed germination.     

Chemical composition of dietary fiber and polyphenols of five different varieties of wine grape pomace skins

The skins of two white wine grape pomace (WWGP) and three red wine grape pomace (RWGP) from US Pacific Northwest were analyzed for their dietary fiber (DF) and phenolic composition. DF was measured by gravimetric–enzymatic method with sugar profiling by HPLC–ELSD. Insoluble DF composed of Klason lignin (7.9–36.1% DM), neutral sugars (4.9–14.6% DM), and uronic acid (3.6–8.5% DM) weighed more than 95.5% of total DF in all five WGP varieties. WWGP was significantly lower in DF (17.3–28.0% DM) than those of RWGP (51.1–56.3%), but extremely higher in soluble sugar (55.8–77.5% DM vs. 1.3–1.7% DM) (p < 0.05). Soluble polyphenols were extracted by acidified 70% acetone and measured spectrophotometrically. Compared with WWGP, RWGP had higher values in total phenolic content (21.4–26.7 mg GAE/g DM vs. 11.6–15.8 mg GAE/g DM) and DPPH radical scavenging activity (32.2–40.2 mg AAE/g DM vs. 20.5–25.6 mg AAE/g DM) (p < 0.05). The total flavanol and proanthocyanidin contents were ranged from 31.0 to 61.2 mg CE/g DM and 8.0 to 24.1 mg/g DM, respectively for the five WGP varieties. This study demonstrated that the skins of WGP can be ideal sources of DF rich in bioactive compounds.     

豆渣中可溶性膳食纤维提取工艺优化

目的 探究空化射流联合复合酶法对豆渣可溶性膳食纤维（soluble dietary fiber,SDF）得率、抗氧化活性及官能团的影响。方法 采用单因素和响应面实验设计优化空化射流联合复合酶法提取工艺条件,测定提取后SDF的1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除率和红外光谱。结果 豆渣SDF最佳提取条件为：空化射流处理压力0.3 MPa,复合酶添加量为6%,料液比为1:30 (g/mL),豆渣SDF提取率为18.21%;此条件下得到的SDF具有较高的抗氧化活性,在SDF质量浓度为2.5 mg/mL时,对DPPH自由基抑制率为73.06%;红外光谱图显示经联合方法提取的豆渣SDF官能团成分没有发生变化。结论 空化射流联合复合酶法可以有效提高豆渣SDF提取率,为提高豆渣应用价值提供理论支撑。     

Production of antioxidant high dietary fiber powder from carrot peels

The feasibility study of using carrot peels, by-products from food industry, as a starting raw material to produce antioxidant dietary fiber powder was investigated in this work. The effects of blanching and hot air drying (60-80 °C) on the drying kinetics and physicochemical properties of dietary fiber powder were first evaluated. The results showed that blanching had a significant effect on the fiber contents and compositions, water retention and swelling capacities of the fiber powder. In contrast, drying temperature in the selected range did not affect the hydration properties. In terms of the antioxidant activity, thermal degradation during both blanching and drying caused a decrease in the contents of β-carotene and phenolic compounds, hence leading to the loss of antioxidant activity of the final product.     

Effects of polyvinylchloride films and edible starch coatings on quality aspects of refrigerated Brussels sprouts

To extend shelf life, the effects of polyvinylchloride film (PVC) and edible coatings on quality aspects of refrigerated Brussels sprouts were studied. Starch-based coatings were formulated using glycerol (G), sorbitol (S) or glycerol plus sunflower oil (O). Sprouts so treated as well as uncoated ones were placed on expanded polystyrene trays. Combinations of PVC and coatings (treatments named G-PVC, S-PVC and O-PVC) were also tested. Uncovered trays were maintained as controls. All packages were stored at 0 °C for 42 days and samples were removed every 14 days to determine commercial acceptability, weight loss, surface colour (of sprouts’ heads and bases) and texture. Sprouts in all treatments maintained optimum quality conditions over the first 14 days. At the end of storage, browning of cut zones and losses in weight and firmness were minimised in PVC-packaged sprouts, particularly in G-PVC. Therefore, PVC and G-PVC treatments were selected to evaluate some nutritional quality components. Ascorbic acid and total flavonoid contents remained almost constant while radical scavenging activity increased after 42 days of storage. Thus, PVC and G-PVC treatments showed the best performance for long-term refrigerated storage of Brussels sprouts.     

江蓠藻膳食纤维吸附脂肪、胆固醇和胆酸钠的研究

比较江蓠藻水溶性膳食纤维、水不溶性膳食纤维和总膳食纤维对脂肪、胆固醇和胆酸钠的体外吸附作用.结果表明,3种膳食纤维对脂肪、胆固醇和胆酸钠均有一定的吸附作用,其中,江蓠藻水溶性膳食纤维对于胆固醇和胆酸钠的吸附能力大于另2种膳食纤维,对脂肪的吸附作用,江蓠藻水不溶性膳食纤维也要强于另2种膳食纤维.说明江蓠藻膳食纤维能减少机体对膳食中脂肪、胆固醇的摄入.     

Effects of abscisic acid on glucosinolate content,isothiocyanate formation and myrosinase activity in cabbage sprouts

Effects of abscisic acid (ABA) on glucosinolate content, isothiocyanate formation and myrosinase activity in cabbage sprouts were investigated. Subsequently, their distributions in different organs were evaluated. ABA (50 μmol L^?1) significantly increased glucosinolate content, isothiocyanate formation and myrosinase activity by 72.65%, 268.15% and 67.69%, respectively, in 5‐day‐old sprouts. Application of ABA alleviated the decrease rate of glucosinolate content and increased the myrosinase activity during germination. Besides, isothiocyanate formation rapidly increased after germinating for 3 days. The glucosinolate content and isothiocyanate formation reduced by 46.51% and 38.01%, respectively, in fluridon (Flu)‐treated sprouts. Cotyledon of ABA‐treated sprouts had the highest glucosinolate content and isothiocyanate formation, indicating that ABA was necessary to enhance the isothiocyanate formation in cabbage sprouts by increasing glucosinolate content and myrosinase activity.     

锦橙皮膳食纤维抗氧化活性研究

目的:提取锦橙皮膳食纤维,研究其对O2-·、·OH、DPPH·三种自由基的清除作用。方法:采用复合酶法对膳食纤维进行提取,采用邻苯三酚自氧化法和Fronton反应对清除O2-·、·OH、DPPH·的效果进行了研究。结果:对O2-.清除率最高为46.28%,对.OH的IC50为3.27mg/mL,对DPPH.的IC50为5.66mg/mL。综上所述,锦橙皮膳食纤维对三种自由基都具有一定的清除作用。     

野生薯蓣膳食纤维的提取及对自由基的清除作用

以薯蓣粉为材料,设计4因素3水平的正交试验,酶法提取膳食纤维。结果表明：0．7％混合酶（晓一淀粉酶与糖化酶质量比为6：1）,处理温度60℃,处理时间80rain,0．5％蛋白酶在60℃处理60min,对淀粉和蛋白质的脱除较彻底。以体外试验研究不同质量浓度（20-140mg／mL）的膳食纤维鲜样和可溶性淀粉对自由基的清除效果,设计3种不同的反应体系：1,1-二苯基-2-苦味肼基自由基（DPPH）、超氧阴离子自由基（O2＋）、羟自由基（·OH）。结果表明：薯蓣膳食纤维对3种自由基都有一定的清除能力,平均消除率分别为53．23％、31．67％、30．38％。对3种自由基清除能力大小顺序为：DPPH自由基〉超氧阴离子自由基〉羟自由基。另外,可溶性淀粉对3种自由基也有轻微的清除能力,其平均清除率分别为2．81％、6．98％、6．48％。     

Effect of dietary fiber from sugarcane bagasse and sucrose ester on dough and bread properties

The suitability of an emulsifier, sucrose ester, to enhance the proportion of dietary fiber in white pan bread was examined. The substitution of dietary fiber from sugarcane bagasse and a commercial dietary fiber (Solka Floc^® 900) were varied from 0 to 15 g/100 g of wheat flour mass. Expansion and stickiness of dough, volume, specific volume, firmness and springiness of bread, including sensory evaluation all decreased as each of dietary fiber increased. Bread properties improved with sucrose ester addition. Bread made by 10 g/100 g of each dietary fiber substitution, was scored favorable by consumer when sugar ester was added at 1.5 g/100 g as wheat flour mass.     

Dietary fibre content and antioxidant activity of Manto Negro red grape (Vitis vinifera): pomace and stem

The general composition of two by-products of the vinification process of the Manto Negro red grape (Vitis vinifera) variety, namely pomace and stem, were determined. Both by-products present high contents of total dietary fibre (TDF), comprising three fourths of the total dry matter. The pomace had high protein (12.2%) and oil (13.5%) values and the stem large amounts of extractable polyphenols (11.6%). Due to the high fibre content, the soluble dietary fibre (SDF), insoluble dietary fibre (IDF), uronic acids (UA) and Klason lignin (KL) were analysed in both samples. Notable were the high percentage of soluble fibre (15%) in relation to the total dietary fibre for the pomace, as well as the high content of Klason lignin (KL) in both by-products, especially in the stem (31.6%). This fraction (KL) has important amounts of condensed tannins (CT) and resistant protein (RP).     

膳食纤维及短链脂肪酸对肠道微生物组成的影响

膳食纤维是一类不能被胃肠道分解的碳水化合物,但它可以被肠道微生物降解成短链脂肪酸。膳食纤维和短链脂肪酸对机体的代谢和健康具有重要的保健功能。本文概括了膳食纤维的类型和来源不仅影响肠道微生物的组成和功能,还影响着宿主与微生物之间的相互作用。重点阐述了膳食纤维能够通过肠道微生物产生短链脂肪酸的机制,进一步探讨了短链脂肪酸、阿魏酸、琥珀酸等对肠道微生物的组成、多样性的影响。     

Status of dietary fiber contents in pigmented and non-pigmented rice varieties before and after parboiling

Five different varieties of paddy (four pigmented and one non-pigmented) were shelled and milled in pre and post parboiled form, their dietary fiber contents were estimated. Under similar conditions of milling, raw rice showed a high degree of polish (DOP), 9–12 g/100 g and parboiled rice showed low DOP, 4.6–6.6 g/100 g. Dietary fiber content was high in pigmented rice, 9–10 g/100 g compared to non-pigmented, ∼6 g/100 g. Soluble fiber content in pigmented head rice (dehusked) varied from 1 to 1.5 g/100 g and in its brokens varied from 0.45 to 1.45 g/100 g. Dietary fiber content was low by about 1% in parboiled rice. In the parboiled rice of pigmented varieties, the total fiber content varied from 7.95 ± 0.15 to 9.05 ± 0.25 g/100 g and the soluble fiber content varied from 0.7 to 0.9 g/100 g. In milled parboiled rice the respective values were 5 ± 0.4 to 6 ± 0.1 g/100 g and 0.85 ± 0.05 to 1.25 ± 0.05 g/100 g. However, the soluble fiber content in the non-pigmented brown rice, IR-64 remained same after parboiling, 0.75 ± 0.5 g/100 g. Milled parboiled rice showed higher soluble dietary fiber compared to milled raw rice. In conclusion, dietary fiber was high in pigmented rice varieties when compared with non-pigmented rice.     

Effects of genotype and environment on β-glucan and dietary fiber contents of hull-less barleys grown in Turkey

In this study, the effects of cultivar and environment on β-glucan and total dietary fibre (TDF) contents and various quality characteristics of hull-less barley samples grown in Turkey were investigated. There were significant differences among the barley genotypes and different locations in terms of β-glucan and TDF content (p < 0.05). Significant correlations were found between β-glucan content and some quality criteria (sieve analysis and 1000 kernel weight). The correlations between TDF and grain yield, hectolitre weight, 1000 kernel weight and protein content were also generally significant. These results indicated that environmental and genetic factors are involved in the total β-glucan content of barley.     

Nutritional comparison of fresh,frozen, and canned fruits and vegetables II. Vitamin A and carotenoids,vitamin E,minerals and fiber

In this second part of our review, we examine the literature for changes in carotenoids, vitamin E, minerals, and fiber due to processing, storage, and cooking of fresh, frozen, and canned fruits and vegetables. While inconsistencies in methodology and reporting methods complicate interpretation of the data, the results show that these nutrients are generally similar in comparable fresh and processed products. The higher levels of carotenoids typically found in canned as compared to fresh products may be attributed to either reporting results on a wet rather than dry weight basis, greater extractability, or differences in cultivars. There are relatively few studies on processing, storage, and cooking effects on vitamin E in fruits and vegetables. Further research is needed to understand nutritional changes in those few fruits and vegetables rich in vitamin E, such as tomatoes. Minerals and fiber are generally stable to processing, storage, and cooking, but may be lost in peeling and other removal steps during processing. Mineral uptake (e.g., calcium) or addition (e.g., sodium) during processing can change the natural mineral composition of a product. Sodium concerns in canned food can be addressed by choosing products with no salt added. Since nutrient content varies considerably by commodity, cultivar, and postharvest treatments, inclusion of a wide variety of fruits and vegetables in the diet is encouraged. Copyright © 2007 Society of Chemical Industry     

Effect of dietary fiber and butyric acid on lysosomal enzyme activities in streptozotocin-induced diabetic rats

The effect of dietary fiber and butyric acid on lysosomal enzyme activities in different tissues of streptozotocin-induced diabetic rats was studied by analyzing the specific activities of N-acetyl-β-d-glucosaminidase, β-d-glucuronidase, β-d-galactosidase, and acid phosphatase in various tissues. An alteration in the activities of these lysosomal enzymes in different tissues was observed in streptozotocin-induced diabetic rats. Dietary fiber and butyric acid supplementation at 500 mg/kg body weight/day was found effective in modulating the altered glycosidases activity in liver, spleen, heart, lungs, testis, and brain during diabetes. Our results also indicated that butyric acid along with dietary fiber is involved in minimizing the oxidative stress-induced tissue damage thereby regulating the altered enzyme activities in different tissues during diabetes.