Folate fortification of white and whole-grain bread by adding Swiss chard and spinach. Acceptability by consumers

The aim of this work was to study the effect of bread-making on the content of endogenous folate of white and whole-grain bread fortified with either Swiss chard or spinach at 20 g/100 g and 40 g/100 g measured by HPLC (H4-folate and 5-CH3-H4-folate); and to assess the sensory acceptability of folate-fortified breads compared to non-fortified breads. The fortification of breads with 20 g/100 g and 40 g/100 g vegetables significantly (p < 0.001) increased the total folate content (from 19.9 to 57.9 μg/100 g in white bread and from 37.4 to 75.5 μg/100 g in whole-grain bread). Moreover, 40 g/100 g Swiss chard- and spinach-fortified breads obtained higher scores in overall acceptability than 20 g/100 g fortified or control bread for both white and whole-grain breads. The consumption of two servings (56 g each) per day of 40 g/100 g fortified bread would meet the daily folate requirements by 14.3–21.8% in adults and 9.6–14.5% in some special states like women of child-bearing age.     

Distribution of Niclosamide Residues in Meat and Internal Organs of Common Carp

Niclosamide is applied for the treatment of the disease of common carp hatchlings caused by Bothriocephalus acheilognathi. One of the main characteristics of this drug is a short half-life in water. A series of experiments were performed to determine the distribution of niclosamide residues in the organs and meat of the carp, in controlled conditions. It was shown that 72.42% of niclosamide was deposited in the liver, 18.79% in the kidney and 7.79% in the spleen. However, only about 3% of deposited niclosamide was detected in meat. This drug provides rapid and effective treatment of fish, completely eliminating the tapeworms.     

茶多酚对草鱼冷藏过程脂肪酸的影响

采用GC-MS法研究草鱼鱼肉脂肪酸的组成及茶多酚对鱼肉脂肪酸变化的影响.测定在4℃贮藏条件下,添加不同含量茶多酚的鱼肉中各脂肪酸的相对含量.结果表明:草鱼鱼肉中含有18种脂肪酸,其中饱和脂肪酸占29.29％,不饱和脂肪酸占70.68％;在4℃贮藏过程中,荼多酚对脂肪酸有明显的保护作用,添加了茶多酚的试验组中各脂肪酸含量都明显高于空白组,综合分析确定:茶多酚添加量为0.03％效果最佳.     

茶多酚对草鱼鱼肉蛋白质流变学特性的影响

采用不同浓度的茶多酚(Tea Polyphenol,TP)处理新鲜草鱼鱼肉,利用分光光度计、质构仪、流变仪及扫描电镜对4℃贮藏的草鱼鱼肉蛋白质的乳化性、凝胶性、流变性及超微结构随贮藏时间的变化进行研究。结果表明,添加0.03%以上TP能延缓草鱼鱼肉蛋白质的乳化性能的降低,提高乳化稳定性;添加0.05%以上TP能增加鱼糜的凝胶强度,降低鱼肉制品的储藏模量和损耗模量,清除由于脂类氧化而产生的自由基,延缓鱼肉蛋白质的降解速度。在试验范围内,TP添加浓度越高,对鱼肉蛋白的流变学特性的保护作用效果越好,但不具备剂量效应,0.05%TP试验组与0.07%TP试验组作用效果差异不显著,考虑到生产成本,草鱼冷藏期间建议添加0.05%的TP。     

鲤鱼土腥味成分的检测与去除

采用涂有聚二甲基硅氧烷二乙烯笨(PDMS-DVB)涂层的固相微萃取头分别对鲤鱼皮、血、肉的挥发性成分进行萃取,通过气质联用仪分离鉴定,分别检测出20种、23种和19种有效挥发性成分,初步探明了鲤鱼土腥味的组成,为鱼类土腥味的改变或去除提供理论基础.将鲤鱼肉经盐碱水漂洗、香辛料浓缩液浸泡和70℃加热后,经相同的顶空固相微...     

The effect of three organic pre-harvest treatments on Swiss chard (Beta vulgaris L. var. cycla L.) quality

Despite the increasing interest in organic products, our understanding of how different organic treatments affect fruit and vegetable quality is still limited. The effect of three organic pre-harvest treatments [effective microorganisms (EM), a fermented mixture of effective microorganisms with organic matter (EM-Bokashi + EM), and an auxiliary soil product (Greengold^®)] on Swiss chard quality was evaluated. The Swiss chard was analyzed 8 and 19 weeks after sowing. The treatments did not notably modify the physical and chemical quality of the chard when compared with control plants. Chard harvested 19 weeks after sowing showed greater differences in nutritional quality than chard harvested 8 weeks after sowing. Control plants had higher water content than the plants treated with EM, EM-Bokashi + EM and Greengold^®. Chards treated with EM-Bokashi + EM had lower ascorbic acid content and higher phosphor and magnesium content than control plants. Application of EM to plants induced higher levels of calcium compared with non-treated plants.     

Shelf-life extension of crucian carp (Carassius auratus) using natural preservatives during chilled storage

The effect of the natural preservatives, tea polyphenols and rosemary extract, on microbiological [total viable count (TVC)], chemical [pH, total volatile base nitrogen (TVB-N), K-value and thiobarbituric acid (TBA) values], texture and sensory changes of air-packaged whole crucian carp (Carassius auratus) stored at 4 ± 1 °C was investigated for 20 days. The shelf-life of crucian carp was found to be 7–8 days for untreated group (control), 13–14 days for tea polyphenols group and 15–16 days for rosemary extract treated group according to sensory assessment results, for which the corresponding microbiological assessment also showed an increased shelf-life. Meanwhile, the increases of pH, TVB-N, K-value and TBA values were significantly delayed in both treated groups of samples compared to the control group. Thus, either tea polyphenols or rosemary extract could be used as potential preservatives to extend the shelf-life of crucian carp during chilled storage.     

Characterization of Native Microbial Population of Swiss Chard (Beta vulgaris, type cicla)

The native microflora of fresh Swiss chard (Beta vulgaris, type cicla) was quantified and characterized. The populations concentration of the different microorganism groups presented great variability among different lots, that was attributed to their separated histories. The mean populations of the native microflora were: 3.0×10⁶ cfu/g for mesophilic, 3.25×10⁵ cfu/g for psycrotrophic microorganisms, 9.23×10³ cfu/g for lactic acid bacteria, 2.95×10³ cfu/g for total coliforms, 1.21×10⁴ cfu/g for yeasts, 4.75×10³ cfu/g for molds and 4.2×10³ cfu/g for staphylococci. The following species were identified: Micrococcus roseus, Micrococcus sedentarius, Lactobacillus paracasei subsp. paracasei, Bacillus subtilis, Bacillus pumilus, Alternaria spp., Botrytis spp.,Aspergillus spp., Microsporium spp., Fusarium spp. and Trychophyton spp. Neither fecal nor pathogens were found. Immersion of Swiss chard leaves in tap water at 18 °C for 4 min reduced microbial populations but did not accomplish more than 70 percent removal in any of the populations under study.     

Effects of E‐beam irradiation and vacuum packaging on biogenic amines formation in common carp (Cyprinus carpio) fillets

The effects of vacuum packaging followed by E‐beam irradiation treatment on the shelf life of common carp (Cyprinus carpio) fillets were studied by measuring biogenic amines and sensory analysis. Samples were irradiated at doses of 0.10, 0.50, 1.0 and 2.0 kGy. Putrescine, cadaverine, histamine and tyramine showed very good correspondence with the irradiation dose and the time of storage. Spermine, spermidine, tryptamine and phenylethylamine did not show statistically significant changes with the time of storage. According to the sensory assessment and biogenic amines index (BAI), the shelf life of unirradiated common carp fillets was found to be approximately seven days. The 1 and 2 kGy irradiation doses extended the shelf life of samples up to 66 and 77 days, respectively. High values of correlation coefficients (r < ?0.86) between BAI and sensory evaluation indicated that BAI could be considered as a quality indicator of common carp fillets.     

鲤鱼肌原纤维蛋白酶解及产物抗氧化性的研究

从鲤鱼肌肉中提取肌原纤维蛋白,以水解度(DH)和邻苯三酚自由基(DPPH)清除率为指标,探讨了木瓜蛋白酶、碱性蛋白酶和胰蛋白酶水解鲤鱼肌原纤维蛋白的酶解效果。研究表明,木瓜蛋白酶是制备鲤鱼肌原纤维蛋白酶解物的优选蛋白酶,通过单因素及正交试验获得了最佳酶解条件:温度55℃、pH7、酶用量1 000 U/g、底物浓度4%、酶解时间2 h;在此优化条件下鲤鱼肌原纤维蛋白酶解物对DPPH清除率为82.73%,表现出较强的抗氧化活性水平。     

壳聚糖对冷藏鲤鱼片品质变化的影响

为了解壳聚糖处理对4 ℃冷藏条件下鲤鱼片品质的影响,测定对照组、T1组（20 g/L壳聚糖＋体积分数0.5%醋酸）、T2组（体积分数0.5%醋酸）鲤鱼片4 ℃冷藏条件下感官分值、菌落总数（total aerobic counts,TAC）、挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、pH值和生物胺含量等指标的变化,分析壳聚糖对冷藏鲤鱼片品质的影响。结果表明：3 组鲤鱼片的感官分值随着贮藏时间的延长逐渐降低,对照组鲤鱼片在贮藏8 d后感官不可接受,T1组鲤鱼片的总体感官分值高于T2组;3 组鲤鱼片的TVB-N含量在贮藏期间呈增长趋势,贮藏10 d时,对照组鲤鱼片的TVB-N含量与T1、T2组差异显著（P＜0.05）,对照组鲤鱼片贮藏10 d时的TVB-N含量达31.37 mg/100 g,而T1组仅为13.07 mg/100 g;T1组鲤鱼片TAC的增长速率显著低于对照组和T2组（P＜0.05）;腐胺、尸胺的含量随着贮藏时间的延长而升高,贮藏后期,T1、T2组鲤鱼片的腐胺含量显著低于对照组（P＜0.05）。壳聚糖的加入可以改善冷藏鲤鱼片的品质,并可将货架期延长2 d。     

魔芋粉对鲤鱼肌原纤维蛋白凝胶特性的影响

从鲤鱼背部肌肉中提取肌原纤维蛋白,分别添加0.05、0.10、0.15、0.20g/100mL的魔芋粉,研究其在不同加热温度(70、80、90℃)和不同NaCl浓度(0.05、0.10、0.15、0.20mol/L)条件下对肌原纤维蛋白凝胶的硬度、弹性、白度和保水性的影响。结果表明：相同魔芋粉添加量条件下,加热温度80℃时形成的肌原纤维蛋白凝胶的硬度和弹性显著高于70℃和90℃(P＜0.05);90℃时凝胶白度高于70℃和80℃;90℃时保水性显著高于70℃时的保水性(P＜0.05),与80℃的凝胶保水性差异不显著(P＞0.05)。在此条件下,随着NaCl浓度增加,凝胶的硬度和弹性增大;肌原纤维蛋白凝胶的保水性显著提高。同一温度条件下,添加0.10g/100mL魔芋粉的蛋白凝胶硬度达到最大值,且80℃时硬度最大为129g,凝胶的白度随着魔芋粉质量浓度增加呈现下降趋势,保水性随着魔芋粉质量浓度的增加而增大;添加NaCl可以显著提高凝胶的白度。     

Trials to Reduce Nitrate and Oxalate Content in Some Leafy Vegetables. 2. Interactive Effects of the Manipulating of the Soil Nutrient Supply,Different Blanching Media and Preservation Methods Followed by Cooking Process

Experiments were carried out to find ways to prevent undesirably high nitrate contents in lettuce and high nitrate and oxalate contents in spinach. Treatments included manipulating the soil nutrient supply and the effects of processing and cooking on the reduction of nitrate and oxalate contents, and the maintenance of vitamins and minerals in the spinach. Best lettuce and spinach qualities, ie highest vitamin and mineral contents with lowest nitrate and oxalate levels, were achieved by fertilising them either with farm yard manure (FYM) or Ca(NO₃)₂+(NH₄)₂SO₄(1: 1)+N-serve (nitrification inhibitor), at the rate of 178·5 kg N ha^-1. High spinach yields were also obtained by fertilisation with urea at 178·5 kg N ha^-1, but resulted in high nitrate and oxalate levels. Losses of vitamins A, B₁, B₂, niacin and C as well as minerals Ca, Fe, Mg, Na, K and P from spinach were smaller following freezing compared with canning, especially when 0·1% calcium citrate and 0·01% sodium ascorbate solutions were used for blanching at ∽77°C for 2 min. © 1997 SCI.     

短期饥饿对草鱼肌肉质构的影响

研究短期(15 d)饥饿对草鱼肌肉常规营养组成及质构参数的影响,为养殖生产实践中草鱼品质改善的调控提供理论依据与参考资料。选取达到上市规格的普通草鱼和普通草鱼连续饥饿15 d的瘦身草鱼各10尾,分别测定其常规营养成分、理化参数、脂肪酸组成、肌纤维直径和主要质构指标。并根据短期饥饿后草鱼情况延长饥饿时间到50 d测定营养组成和质构参数。结果显示:短期饥饿(15 d)后,草鱼肌肉水分、粗蛋白和粗脂肪含量均无显著变化,而硬度、胶着性和咀嚼性显著下降,灰分p H和电导率显著上升,短期饥饿使PUFA(碳二十烷酸)的含量显著增加。短期饥饿(15 d)后,对鲜味有影响的特征性氨基酸(谷氨酸和天门冬氨酸)上升,而对甘味有影响的特征性氨基酸(丙氨酸和甘氨酸)下降。草鱼饥饿50 d的补充数据显示随着饥饿时间的延长,与对照组相比,其水分和粗脂肪含量显著降低,硬度、咀嚼性、胶着性相比饥饿15 d的草鱼均显著升高,但硬度和胶着性仍显著低于对照组,咀嚼性与对照组间不存在显著差异,灰分含量显著高于对照组。因此,从草鱼肌肉脂肪含量、硬度、胶着性及咀嚼性等常规营养及质构指标综合考虑,如果以降低肌肉脂肪含量为饥饿处理的目标之一,由于短期饥饿(15 d)并不能有效降低草鱼肌肉脂肪含量,饥饿处理50 d效果更好。      

透明质酸涂膜结合微冻贮藏对鲜切鲤鱼肉保鲜效果的研究

为研究透明质酸(HA)涂膜对鲤鱼微冻贮藏过程中保鲜效果的影响,以鲜切鲤鱼为原料,将鲤鱼肉表面涂膜不同浓度HA(0、0.3%、0.6%、0.9%),在-3 ℃的微冻环境下贮藏,探讨HA对鲤鱼肉微冻贮藏物性和生化指标的影响。结果表明:HA结合微冻贮藏能较好地延缓鲤鱼肉挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBARS)、pH、电导率的升高,抑制持水力的下降,保持较好的质构和色泽。微冻贮藏24 d,0.9% HA处理的鲤鱼肉保鲜效果最好,持水力和剪切力降幅最小(p<0.05),白度变化较小,TVB-N为10.98 mg/100 g,TBARS为0.13 mg/kg,电导率为900 μS/cm。主成分分析(PCA)表明,微冻贮藏条件下,HA处理对鲤鱼肉持水力、剪切力、电导率影响较大,HA涂膜可明显减缓贮藏鱼肉TVB-N和TBARS增加,0.9% HA涂膜处理的鲤鱼肉微冻保鲜效果较好。