山药营养面条的研制

通过正交试验和感官评价方法,得到山药面条的最佳配方为山药粉2%,食盐1%,复合添加剂0.2%。各因素对山药面条的影响顺序为山药粉>复合添加剂>食盐,通过检测和观察面条烹煮特性、物性指标和微观结构,对山药面条品质性状进行了分析和评价。山药营养面条品质好,具有山药清香,营养丰富。     

冷冻龙虾仁辐照灭菌保鲜工艺技术研究

冷冻龙虾仁在我国水产品出口中占有较大的比例,由于高温加工,微生物很难控制到符合欧美标准。采用γ射线低剂量保温辐照工艺处理冷冻龙虾仁,结果表明:一般有效剂量控制在1.5 kGy即可使杂菌总数控制在1万个/g以下。在0~10 kGy处理剂量下,辐照对蛋白质无明显影响,并延长了保鲜期。研究还探讨了保温情况下的一整套灭菌工艺,使辐射剂量不均匀度控制在2以内,使被处理的产品保持原有的色、形,不回化。     

A novel approach for improving yeast viability and baking quality of frozen dough by adding biogenic ice nucleators from Erwinia herbicola

Freezing deteriorates the baking quality of frozen bread dough by causing lethal injury to yeast cells and depolymerization to the gluten network. To investigate the potential of biogenic ice nucleators in frozen food applications, the effect of extracellular ice nucleators (ECINs) from Erwinia herbicola on the baking quality of frozen dough upon three freeze/thaw cycles were investigated. With addition of ECINs to the activity of 2.4 × 10⁶ units per gram of dough, hardening of bread crumb caused by three freeze/thaw cycles was alleviated by about 50% compared to the control. Additionally, the bread from frozen dough with added ECINs showed 50% larger specific volume compared to the control. The mechanism of cryoprotective effects from ECINs was possibly that ECINs helped in preserving the viability of yeast cells during freeze/thaw cycles. ECINs were able to improve the viability of log-phase and stationary-phase yeast cells in suspensions by about 100 and 10 fold, respectively, and viability of yeast in the frozen dough by 17%. This study revealed the potential of ECINs as a cryoprotectant for applications in the food and biotechnology industries.     

精油对熟制鸡胸肉中产气荚膜梭菌抑制效果预测模型研究

为研究不同香辛料精油对熟制鸡胸肉中产气荚膜梭菌(C.perfringens)的影响,该文以肉桂精油、艾草精油和茴香精油为研究对象,对C.perfringens标准株(ATCC13124)和分离株(C1)抑菌效果,筛选出抑制最佳浓度,采用BP神经网络构建C.perfringens的生长/残存动力学模型,并以相关系数(R~2)和均方根误差(RMSE)评价模型精度,以期快速预测不同精油浓度条件对C.perfringens影响。结果表明:经肉桂精油处理后的ATCC13124和C1浓度最低,抑制效果最强;采用BP神经网络模型构建不同精油对熟制鸡胸肉中C.perfringens的预测模型,肉桂精油对ATCC13124和C1的R~2分别为0.963和0.976,RMSE分别为0.327和0.271CFU/g,预测效果最佳;利用验证集对模型鲁棒性进行验证,结果表明R~2均在0.917以上,RMSE在0.200～0.640 CFU/g之间,结果表明,BP神经网络模型可以较好的预测熟制鸡胸肉中产气夹膜梭菌的生长/残存情况;为肉类加工过程中控制C.perfringens提供理论依据。     

甘薯茎尖粉在挂面生产中的应用

为了利用甘薯茎尖丰富的营养成分,该试验通过复因素试验分析测定了添加甘薯茎尖粉和淀粉磷酸酯对挂面弯曲断条率、烹煮时间、烹煮损失、熟断条率和吸水率等品质指标的影响.结果表明:甘薯茎尖粉和淀粉磷酸酯的不同添加量对挂面弯曲断条率的影响较大,且二者存在交互效应;添加甘薯茎尖粉对于挂面烹煮时间、烹煮损失、熟断条率和吸水率均无显著影响,而处理间及添加淀粉磷酸酯对挂面上述4个品质指标均有极显著影响.经综合分析最终确定小麦粉、甘薯茎尖粉、淀粉磷酸酯按100:1.5:7的比例混合为生产挂面的较佳配方,经与市售挂面相比较,发现采用此配方可以生产出营养价值高且质量合格的甘薯茎尖挂面.     

Post-thawing Sperm Quality in Chilean Purebred Stallions: Effect of Age and Seasonality

In this work, we investigated the influence of age and seasonality on sperm motility and DNA fragmentation in post-thawing semen from Chilean Purebred Stallions (CPS), a horse breed presenting the oldest genealogy record in South America with an interesting reproductive industry. Despite that semen from aged CPS is frozen all year round, there is a lack of studies characterizing the breed semen freezability in accordance with age and seasonality. Twenty fertile CPS were grouped into the young group, the middle group, and the aged group. Ten ejaculates from each stallion were obtained by using an artificial vagina during summer (December) and winter (July) and directly frozen. Subsequently, the frozen semen was thawed and analyzed by a computer-assisted semen analysis and flow cytometer assessing progressive motility, mean velocity, and DNA fragmentation spermatozoa. Kruskal–Wallis test and Pearson’s correlation were used to determine statistical differences among groups and correlation among variables (P ≤ .05). Both spermatozoa motility traits decreased progressively in accordance with age and seasonality, showing the lowest values in the aged group during winter and the highest values in the young group during summer. Deoxyribonucleic acid fragmentation increased significantly in accordance with age and seasonality being highest in the aged group during winter and lowest in the young group during summer. Post-thawing sperm quality showed a negative correlation with the age of the stallions and a positive correlation with the normal sperm morphology before freezing. These results allow the conclusion that age and seasonality are important factors that need to be considered during the selection of CPS for reproductive programs.     

Sensory and physicochemical properties of whole wheat salted noodles under different preparations of bran

Whole wheat products have gained popularity in recent years due to the health and nutritional benefits, with Asian salted noodles as one formulation. However, there is a general perception of decreased product quality and sensory acceptance of whole wheat noodles This study examined changes to sensory properties, texture (tensile and compressive strength), color, and cooking loss of noodles prepared from blends of wheat flour and bran that underwent five forms of hydro, thermal, pressure and their combined treatments: autoclaving, extrusion, jet-cooking, puffing, and roasting. Including the control (bran without processing) all six treatments were deemed palatable by sensory panel evaluation despite having statistically significant differences in physiochemical and sensory properties. For instance, 10 of the 22 sensory properties demonstrated significant differences among treatments. Bran processing tended to result in weaker (tensile and compressive strength) and stickier noodles while allowing for greater uptake of water during cooking.     

面条改良乳化剂在挂面中的应用研究

面条改良乳化剂是一种以单甘脂、卵磷酯或色拉油为有效成分的复配型的水包油型乳液。利用粉质仪和拉伸仪测定,研究了面条改良乳化剂在挂面中的使用效果及合适的添加量。并结合实际的应用效果表明,使用面筋质较好、含量较高的面粉添加面条改良乳化剂制作挂面时,对挂面的改良效果明显;而对软质面粉还可增添少量的廉价的无机盐类添加剂或蛋白质类进行复配,可制取优质挂面。     

Dietary fishmeal levels affect the volatile compounds in cooked muscle of farmed large yellow croaker Larimichthys crocea

A comparative study on the volatile compounds in cooked muscle of wild and farmed large yellow croaker (LYC) was conducted. The two farmed LYC groups were fed with diets containing 44% (CF) and 25% (LF) of fish meal (FM) respectively. Results showed that 48 volatiles, including aldehydes, alcohols, ketones, hydrocarbons, aromatics, acids, esters, furans and miscellaneous compound, were detected in cooked fillets. The LF group had significantly lower amounts of total aldehydes and ketones, higher content of miscellaneous compound in cooked fillets than that in the CF and wild groups (p < .05). Compared with the wild group, the LF group had significantly lower amounts of total alcohols, acids and esters, while the CF group had significantly lower amounts of total aldehydes, higher content of total ketones in cooked muscle (p < .05). According to the principal component analysis (PCA), some volatiles (propanal, nonanal, etc.) could be considered as sensitive indicators to classify cooked muscle samples. In conclusion, differences in the volatiles in the cooked muscle between the wild and farmed LYC have been found. Low level of dietary FM (25%) changed the volatile profiles in cooked fillets of farmed LYC. A PCA may be useful to screen potential volatiles to classify cooked muscle samples in this study.     

上海市售扇贝冻品品质评价模型构建及关键影响因素分析.

为分析上海销售端扇贝冻品的品质状况及存在的问题,探究市售扇贝冻品的品质评价方法以及冻藏过程中导致其品质劣变的关键因素,本研究依据冰柜温度、冻藏时间、产品形式、包装方式和摆放位置共5种常见影响因素,对上海市售的11种扇贝冻品商品进行采样,测定白度、解冻损失、蒸煮损失、持水力、回复性、内聚性、弹性、咀嚼性、硬度和感官评分共10项品质指标,利用因子分析构建扇贝冻品品质评价模型,并结合多元线性回归分析确定影响扇贝冻品品质劣变的关键因素。结果显示,扇贝冻品10项品质指标之间存在一定相关性,通过因子分析提取了3个因子成分,累计方差贡献率为73.33%,可以代替原有指标来综合评价扇贝冻品的品质,建立了市售扇贝冻品的品质评价模型：f=0.467f1+0.302f2+0.231f3,其中,f1公因子包括弹性、回复性、内聚性、蒸煮损失和持水力,f2公因子包括硬度、白度和咀嚼度,f3公因子包括解冻损失和感官评分;进一步由多元线性回归分析得出,冻藏时间、冰柜温度和产品形式是影响扇贝冻品品质的关键因素,其他2种因素无显著影响。研究表明,基于因子分析和多元线性回归的方法能够较好地进行扇贝冻品的品质评价并分析导致其品质劣变的影响因素。