The Effect of Prior Frozen Storage (−20°C) on the Quality of Oven-Baked Sardines (Sardina pilchardus)

ABSTRACT

The effect of frozen storage for 3, 30, 60, 90, and 120 days on the quality of sardines baked for 15, 30, and 45 min was studied. The combination of frozen storage with the baking time in linear reduction of yield and moisture led to less juicy products, as well as significant changes in proteins and lipids. A linear increase of C16:0 followed by a linear reduction of C22:6ω-3 was detected due to frozen storage, indicating lipid oxidation. This was also confirmed by the C22:6ω-3/C16:0 and C20:5ω-3/ C16:0 ratios, which were reduced by 36.8 and 32.7%, respectively. The fatty acid profiles of sardine samples were not significantly altered due to oven-baking. A gradual reduction of eicosapentaenoic acid + docosahexaenoic acid (EPA + DHA) of the baked products was observed mainly due to frozen storage. Cholesterol and squalene content increased with increasing the time of baking. A gradual decrease of cholesterol and squalene was observed due to frozen storage.     

兰州拉面制作过程及产品的感官评价方法

【目的】通过试验、验证和统计分析相结合的方法,研究建立一套有科学依据、操作合理的兰州拉面感官评价指标,为拉面产品质量评价、拉面专用粉标准制定、以及拉面专用小麦品种选育提供感官评价方法,为传统食品感官评价方法的建立提供借鉴或参考。【方法】以8种商业小麦粉,以及两种质量差异较大的小麦粉按一定比例混合制备的预混粉为原料,聘请专业拉面师傅实验室制作兰州拉面。按照初步建立的评价方法,拉面师傅评价制作过程感官质量,感官评价小组评价拉面产品感官质量。分析、改进拉面制作过程和产品感官评价方法,测试拉面制作过程感官评价方法、产品感官评价方法的准确性和精确性。【结果】通过同一位拉面师傅对8种商业小麦粉的3次重复试验,以及3位拉面师傅对预混粉的3次重复和相互比较试验建立的拉面感官评价方法,分值可重复,线性拟合性好,方法准确性较高,可用于拉面的感官评价。【结论】经过对拉面感官评价方法的设计、实施和验证试验,最终确定和面难易程度及面团软硬程度、跐面力度及黏手程度、醒发后面团色泽、拉伸力大小、断条扣数及均匀性5项要素为拉面制作过程的评价指标;色泽、表观、硬度、黏性、弹性、光滑性、食味7项要素为拉面产品的感官评价指标。     

常用食品改良剂对马铃薯米粉品质的影响

[目的]研究6种常用食品改良剂对马铃薯米粉品质的影响,为马铃薯米粉的加工应用提供参考依据.[方法]分别将0、0.02%、0.04%、0.06%和0.08%的焦磷酸钠、磷酸氢二钠、瓜尔豆胶和魔芋胶,以及0、2%、4%、6%和8%的绿豆淀粉和谷朊粉添加到马铃薯全粉含量为30%的米粉中,通过单因素试验,测定马铃薯米粉质构、蒸煮损失率和色差的变化.[结果]焦磷酸钠和磷酸氢二钠添加量分别为0.02%和0.08%时可显著提高马铃薯米粉硬度(P<0.05,下同),添加量分别为0.04%和0.06%时马铃薯米粉具有较高的拉伸特性,焦磷酸钠添加量为0.02%的马铃薯米粉蒸煮损失率低于10%;瓜尔豆胶和魔芋胶添加量为0.02%时可有效提高马铃薯米粉的硬度和拉伸性能、降低蒸煮损失率;绿豆淀粉添加量为2%时,马铃薯米粉的质构得到改善,蒸煮损失率低于4%,其添加量为4%时,马铃薯米粉的拉伸性能显著升高;谷朊粉添加量为2%时,马铃薯米粉的质构、拉伸特性及蒸煮性质均有显著改善.但6种食品改良剂在试验添加量范围内均对马铃薯米粉色泽无明显改善效果.[结论]在添加30%马铃薯全粉的条件下分别添加0.04%焦磷酸钠、0.06%磷酸氢二钠、0.02%瓜尔豆胶、0.02%魔芋胶、4%绿豆淀粉和2%谷朊粉,能够显著改善马铃薯米粉的质构和蒸煮特性,实际生产中可依此比例进行调配.     

2014～2015国家特用型甘薯品种南方区域试验广西试点报告

【目的】通过国家甘薯品种南方区域试验,筛选出适合广西地区种植的优良特用型甘薯新品种,为广西甘薯新品种的选育和推广提供依据。【方法】2014~2015年,以宁紫薯1号为对照(CK),在广西南宁对国家甘薯品种南方区域试验的10个特用型甘薯新品种进行品种比较试验,通过鲜薯产量、薯干产量、干物率、熟食味、花青素含量及抗病性等指标对参试品种进行综合评价。【结果】10个参试新品种中,渝紫7号、桂薯131、福薯404、广薯161和龙津薯1号等5个品种鲜薯产量比CK增产12.46%~36.63%,增产达显著(P0.05)或极显著水平(P0.01),其余品种均较CK减产;渝紫7号、广薯161、桂薯131、福薯404、龙津薯1号、湛紫薯1号和龙紫6号薯干产量比CK增产5.30%~54.49%,其余品种较CK减产;各品种干物率均高于CK;总体食味评分在65.00~90.00分,其中渝紫7号、桂薯131、福薯404、广薯161、湛紫薯1号、龙紫6号、泉薯9-6和金薯13号熟食味平均得分在71.25~81.25分,均高于CK(70.00分);各参试品种均抗1种及以上主要甘薯病害。依据国家特用型甘薯鉴定目标,龙紫6号可作为高花青素甘薯品种,渝紫7号、桂薯131、福薯404和广薯161可作为食用型紫薯品种。【结论】高花青素型甘薯品种龙紫6号和食用型紫薯品种渝紫7号、桂薯131、福薯404、广薯161整体表现较好,适于在广西推广种植。     

HACCP在冷冻调理食品生产中的应用

[目的]制定危害分析与关键控制点(HACCP)管理体系,为有效预防、控制或降低冷冻调理集体食品生产过程中可能出现的危害,从而提高产品的质量,确保舰艇出航食品安全卫生。[方法]依据HACCP基本原理以及国家食品企业通用卫生标准、食品厂卫生规范、调理食品生产工艺和规范,对冷冻调理集体食品生产过程中的潜在危害进行系统分析。[结果]建立具体的控制措施,确定原料验收、烹调、真空包装和金属探测4个关键控制点(CCP),制定HACCP计划实施有效的监控。[结论]HACCP质量保障体系在舰艇食品供应站冷冻调理集体食品生产中的应用,能有效保障产品安全卫生,保障舰艇出航饮食质量。     

Cryopreservation of Cooled Semen and Evaluation of Sperm Holding Media for Potential Use in Equine-Assisted Reproduction Procedures

Processing stallion semen for assisted reproductive procedures, such as intracytoplasmic sperm injection (ICSI), requires special considerations regarding cooling, concentrating, and handling of sperm. The aim of experiment 1 was to determine whether cooled semen could be frozen without removal of seminal plasma and at a low sperm concentration while maintaining motile sperm for ICSI selection procedures. In experiment 2, five media for holding stallion sperm were compared to evaluate sperm motility for an interval of time sufficient for ICSI sperm selection procedures. In experiment 1, semen samples from eight stallions were cooled for 24 hours in two extenders, CST (E-Z Mixin-CST “Cool-Store/Transport” Animal Reproduction Systems) and INRA96 (Institut National de la Recherche Agronomique, IMV International Corporation), before being frozen in four freezing diluents, and were evaluated at 0, 45, and 75 minutes after thawing. The cooling extender did not significantly affect sperm motility, but modified French and glycerol egg yolk diluents provided the best sperm motility for frozen–thawed groups. In experiment 2, semen samples from seven stallions were used to test five media for holding sperm. Samples were analyzed for total and progressive motility at hourly intervals. Mean total and progressive motility were not different (P > .05) among groups from 1 through 4 hours. At 5 hours, groups differed (P = .004), with sperm held in Tyrode’s with albumin, lactate, and pyruvate having higher (P < .05) total and progressive motility than all other samples. In conclusion, motile stallion sperm can be obtained after the sperm are cooled for 24 hours, frozen, and thawed; various media are available to maintain sperm motility during equine ICSI selection procedures.     

降温速率对黏性冻土性质的影响研究

本文通过室内试验,对黏性土在不同降温速率条件下的自由膨胀率、无侧限抗压试验进行了研究和总结.研究表明:冻土抗压强度和自由膨胀率均随降温速率的增加呈增大趋势,同时得到了冻土抗压强度和降温速率的数学回归模型.     

冻融作用对坡面侵蚀及泥沙颗粒分选的影响

为了探究冻土和解冻土对水力侵蚀的影响,利用室内模拟降雨试验对冻土和解冻土两种坡面的坡面侵蚀过程及泥沙颗粒分选特征进行了研究。结果表明:在降雨条件下,相对于解冻坡面(TS),冻土坡面(FS)的产流时间提前了173s,而产流量、产沙量分别增加了9%和105%;两种坡面侵蚀过程中的土壤颗粒平均重量直径(MWD)大小次序均为溅蚀颗粒径流冲刷泥沙颗粒,且冻土坡面溅蚀颗粒及冲刷泥沙颗粒MWD均显著大于解冻土坡面(p0.05);随着降雨进行,解冻土坡面侵蚀泥沙中的黏粒、细粉粒含量呈先迅速增大后减少的趋势;粗粉粒和砂粒含量则呈先减小后增大的趋势,侵蚀泥沙逐渐向粗颗粒发展;而冻土坡面各粒级颗粒随时间变化相对稳定。研究成果可为进一步揭示冻融作用下坡面水力侵蚀机理提供一定的参考依据。     

速冻香椿面条的制作

利用现代速冻技术,制做了速冻香椿面条。经过品质检测和感官评价,速冻香椿面条不仅符合消费者口感,具有浓郁的香椿气味,而且可以进行规模化生产。无论是促进香椿产业化,还是促进速冻食品的发展,都具有现实意义。     

乳化剂对面条品质改良的研究

复合使用4种乳化剂(SSL,CSL,DATE,单甘脂)对面条进行品质改良,应用响应面分析法对乳化剂的添加量进行优化,并对乳化剂之间的协同作用进行分析。结果表明,乳化剂对感官评分的影响次序依次为DATE>SSL>CSL>单甘脂;DATE与SSL的交互作用最为强烈,其次是DATE与CSL;乳化剂的最佳添加量为SSL0.048%,CSL0.023%,DATE0.031%,单甘脂0.024%,此时的感官评分为92.1分。