冰温技术结合保鲜剂对南美白对虾品质的影响

研究冰温技术结合4- 己基间苯二酚(4-hexylresorcinol,4-HR)等保鲜剂对延缓虾类黑变和保持品质方面的效果。通过正交试验确定保鲜剂的配方(M),以冻结试验确定冰温贮藏温度,测定贮藏设备的温控范围,通过评定南美白对虾的黑变感官得分,测定多酚氧化酶(PPO)活力、挥发性盐基氮(TVB-N)、pH 值和菌落总数(TBC)等鲜度指标评价保鲜效果差异。结果表明：南美白对虾的冰温带为－ 2.2～0℃,贮藏设备温度波动满足冰温技术要求,M 保鲜剂配方为0.01% 4- 己基间苯二酚+1.5% 柠檬酸+1% 抗坏血酸,冰温能显著减缓TVB-N 值、pH 值和TBC值增加速度,M 配方保鲜剂能有效抑制虾的多酚氧化酶活性和黑变,冰温技术结合M 配方保鲜剂保藏南美白对虾能互补二者优缺点,能显著减低黑变感官得分,PPO 活性、TVB-N、pH 值和TBC 的增长速度。比(4 ± 1)℃冷藏的货架期延长近1 倍。冰温技术结合保鲜剂能有效防止虾类黑变和延长品质货架期。     

南美白对虾复合生物保鲜剂的优选

为解决南美白对虾易腐败以及化学保鲜剂可能引起的食品安全等问题,通过正交试验,将壳聚糖、茶多酚、乳酸链球菌素(Nisin)进行复配,优选出一种复合生物保鲜剂,并验证了其在南美白对虾防腐保鲜中的效果。结果表明：复合生物保鲜剂的优化质量分数配比为壳聚糖1.5%、茶多酚0.1%、Nisin 0.02%;经该复合生物保鲜剂处理后的南美白对虾在(4 ± 1)℃贮藏过程中挥发性盐基氮(TVB-N)在第8 天还未达到30mg/100g,细菌总数在第9天才达到5 × 105 个/g,保持了较好的感官品质,货架期由4d 延长到了7～8d。处理1kg 对虾新增成本为0.17 元,具有较好的应用价值。     

复合生物保鲜剂对南美白对虾保鲜效果的研究

为解决南美白对虾容易腐败变质及黑变等问题,延长其货架期,通过L9(34)正交试验,将银耳多糖、乳酸链球菌肽(Nisin)和溶菌酶3种生物保鲜剂进行复配,筛选出了0.6％银耳多糖、0.03％Nisin和0.05％溶菌酶为最佳配比.在贮藏期间通过对南美白对虾的感官评价、黑变评定、pH值、挥发性盐基氮(total volat...     

4-HR对涂膜南美白对虾的黑变抑制和残留量分析

研究了0.002%4-己基间苯二酚(4-hexylresoreinol,4-HR)+1%壳聚糖(A组)、0.01%4-HR+1%壳聚糖(B组)和0.05%4-HR+1%壳聚糖(C组)在冷藏条件下对生鲜南美白对虾黑变的抑制作用.测定了南美白对虾的黑变感官评价值、多酚氧化酶活性(PPO)、菌落总数(TBC)、挥发性盐基氮(TVB-N)和4-HR的残留量.结果表明,在整个贮藏过程中,C组一直具有最低的多酚氧化酶活性和最低的黑变感官评分,但是在第4d 4-HR的残留量已经超过了1mg/kg;A和B组在4d内黑变感官评分和酚酶活性无显著差异(P>0.05),两组4-HR的残留量分别在第8d和第6d超过1mg/kg,根据TBC、TVB-N的变化可知,A、B、C三组的货架期分别为6、6和8d,而对照组1只有4d.一定浓度的4-HR与壳聚糖复配保鲜不仅能安全和高效地减缓南美白对虾黑变进程,而且能延长货架期.     

复配生物涂膜保鲜液对冷藏南美白对虾的保鲜效果研究

目的探究复配生物涂膜保鲜液对冷藏南美白对虾的保鲜效果。方法以新鲜南美白对虾为原料,通过单因素实验考察壳聚糖、海藻酸钠、明胶及乳酸链球菌素(Nisin)对冷藏南美白对虾货架期的作用。在此基础上优化壳聚糖、海藻酸钠及Nisin所组成的复配涂膜保鲜液的最适配比。结果壳聚糖6 g/L、海藻酸钠8 g/L、Nisin 0.4 g/L组成的最佳配比复合保鲜液涂膜南美白对虾后冷藏保存,冷藏期限可以达到12 d,测得pH值为7.52,感官评分为3分,比对照组延长了6 d。结论南美白对虾涂膜复合保鲜液后,更能隔绝外界接触,抑制细菌繁殖,从而延缓虾肉的腐败变质,具有更好的保鲜效果,为进一步研究南美白对虾货架期与特定腐败微生物关系奠定理论基础。     

乳源抗菌肽复合生物保鲜剂对冷却牛肉货架期的影响

为延长冷却牛肉货架期并建立货架期预测模型,选取乳源抗菌肽、壳聚糖、乳酸链球菌素（Nisin）、茶多酚和丁香精油5 种天然保鲜剂,通过U16（84）均匀试验,以挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、pH值和菌落总数为指标进行分析,确定保鲜剂的适宜添加量为壳聚糖22.5 g/L、Nisin 0.15 g/L、乳源抗菌肽9.7 g/L、茶多酚1.5 g/L、丁香精油13.0 g/L,（4±1）℃条件下冷却牛肉货架期比空白组延长了25 d以上。对于冷却牛肉TVB-N含量,乳源抗菌肽与Nisin、茶多酚、丁香精油之间及Nisin与茶多酚之间具有极显著的交互影响（P＜0.01）,丁香精油与Nisin之间具有显著的交互作用（P＜0.05）。用复合天然保鲜剂处理后的冷却牛肉在－1、2、6 ℃条件下贮藏,运用Arrhenius方程拟合温度对冷却牛肉菌落总数的影响,结果显示不同温度下决定系数R2均大于0.91,货架期预测模型为SL＝2.75×10－9×exp（6 567.2/T）。贮藏温度分别为2、4 ℃和6 ℃时,冷却牛肉的实际货架期分别为61、53 d和47 d,与货架期预测值相比,相对误差均在6%以内,表明建立的模型可以有效预测冷却牛肉在－1～6 ℃贮藏条件下的货架期。     

流化冰结合防黑剂、抑菌剂对南美白对虾的保鲜效果

为探索南美白对虾的鲜度保持和黑变现象抑制方法,采用流化冰结合防黑变剂（4-己基间苯二酚（4-hexylresorcinol,4-HR）、植酸钠）、抑菌剂（稳定态二氧化氯,ClO2）处理方式,检测贮藏过程中南美白对虾感官、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、菌落总数、质构及多酚氧化酶（PPO）活性变化情况。结果表明,贮藏12 d后,流化冰保鲜对虾头部褐变较严重、肌肉尚有弹性;流化冰结合4-HR或植酸钠、ClO2保鲜对虾,头部仅轻微褐变,肌肉紧密有弹性,感官品质明显优于单纯流化冰组;其中以流化冰结合0.030 g/L4-HR、0.05 g/L ClO2保鲜对虾的感官品质（L*、b*值）保持作用最佳。贮藏16 d后,流化冰保鲜对虾TVB-N值、菌落总数、弹性、咀嚼性和PPO活性,依次为9.43 mg/100 g、6.21（lg（CFU/g））、0.56 mm、7.43 mJ和10.83 U/g;流化冰结合0.030 g/L 4-HR、0.05 g/L ClO2保鲜对虾,以上各指标分别为15.87 mg/100 g、4.90（lg（CFU/g））、0.80 mm、8.55 mJ和7.67 U/g,该处理保鲜效果显著优于单纯流化冰组（P＜0.05）。研究表明,流化冰结合4-HR、ClO2处理,可满足南美白对虾捕后保鲜、远途运输及市场销售要求。     

纳米TiO_2/壳聚糖复合保鲜剂在南美白对虾保鲜中的应用

为解决南美白对虾易腐易黑变问题,延长其货架期,利用不同质量分数的纳米TiO2/壳聚糖保鲜剂处理南美白对虾,并贮藏在(4±1)℃条件下。通过对虾体进行pH值、挥发性盐基氮、菌落总数指标的测定,结合感官评定,表明了纳米TiO2/壳聚糖保鲜剂能够有效地保持南美白对虾的品质,使南美白对虾货架期由原来的4 d延长至7 d,为南美白对虾保鲜技术的推广提供一定的技术支持。     

复合生物保鲜剂对南美白对虾保鲜效果的研究

目的研究复合保鲜剂对南美白对虾的保鲜作用,避免其腐败变质,从而延长其货架期。方法利用不同配比的纳米TiO2/壳聚糖保鲜剂、溶菌酶、蜂胶醇提液复配保鲜剂进行L9(3)4正交试验,通过pH值、感官评分、挥发性盐基氮(TVB-N)、菌落总数指标的测定,对L9(3)4正交试验结果进行方差分析,筛选保鲜剂最佳组合。结果采用0.05%纳米TiO2/1.5%壳聚糖、0.065%溶菌酶、0.7%蜂胶进行复配,南美白对虾的保鲜效果较好。结论复合生物保鲜剂对南美白对虾具有一定的保鲜效果,能使南美白对虾(4±1)℃冷藏条件下的货架期达到8~9 d。     

生物保鲜剂延长冷鲜牛肉货架期的效果

为延长冷鲜牛肉的货架期,保证其贮藏期间的食用品质及安全性,采用单因素试验与正交试验筛选一组 复配生物保鲜剂（乳酸链球菌素、纳他霉素和ε-聚赖氨酸）,并研究其对冷鲜牛肉的保鲜效果。结果表明：复配 生物保鲜剂中3 种保鲜剂的最佳配比为乳酸链球菌素2.5 g/L、纳他霉素1.5 g/L、ε-聚赖氨酸3.0 g/L;冷鲜牛肉在 （4±1） ℃条件下贮藏8 d后,其挥发性盐基氮值为19.84 mgN/100 g,属于二级鲜肉;菌落总数较对照组降低2 个 数量级,表明复配生物保鲜剂能够有效抑制腐败菌的增长;贮藏后期,处理组冷鲜牛肉的汁液流失率较对照组减少 1.73%。复配生物保鲜剂可以将冷鲜牛肉的货架期有效延长4 d。     

Melanosis inhibition and 4-hexylresorcinol residual levels in deepwater pink shrimp (Parapenaeus longirostris) following various treatments

Inhibition of melanosis was studied in pink shrimp (Parapenaeus longirostris) treated on shipboard with various concentrations of 4-hexylresorcinol (4-HR)-based formulations. Treatments, applied by dipping and dusting, were carried out at sea immediately following the catch. A selection of the most effective treatments was made to determine the level of 4-HR residues in the muscle and viscera. 4-Hexylresorcinol proved effective at extending shelf-life over that of untreated shrimp at all the concentrations tested. However, the minimum dose of 4-HR to avoid melanosis for at least one week was found to be 0.5%, with a residual level in muscle ranging from ≈80 to 90 mg/kg at day 2 of storage to >200 mg/kg after 7 days. Residues around 2–3 mg/kg were shown to be effective to prevent melanosis in pink shrimp only for 2 days from a commercial point of view.     

Effect of cinnamaldehyde on melanosis and spoilage of Pacific white shrimp (Litopenaeus vannamei) during storage

BACKGROUND: Shrimp is a very perishable product and postmortem changes occur rapidly. Sulfiting agents were once and are still widely used as a preservative in the shrimp industry. However, the application of sulfite in shrimp may pose a risk to human health. Thus development of a natural preservative as a sulfite alternative to extend the shelf life of Pacific white shrimp is urgently needed. RESULTS: The effects of cinnamaldehyde essential oil (1 and 5 g kg^?1) on the shelf life of Pacific white shrimp stored at 4 °C were investigated. As the concentration of cinnamaldehyde increased, residual polyphenoloxidase (PPO) enzyme activity decreased. Kinetic analysis showed that cinnamaldehyde was a noncompetitive inhibitor for the oxidation of L ‐DOPA (L ‐3,4‐dihydroxyphenylalanine) by PPO of Pacific white shrimp. Based on this study, shrimp treated with 5 g kg^?1 cinnamaldehyde possessed the lowest aerobic plate count, total volatile basic nitrogen, and pH values in all treatments after 10 days of storage. According to the results of L*, cinnamaldehyde showed inhibitory activity toward the formation of melanosis. CONCLUSION: Treatment with cinnamaldehyde could improve the sensory properties and extend the shelf life of Pacific white shrimp to 8 days. Therefore, cinnamaldehyde could be used as a promising natural preservative for inhibiting melanosis and preventing the growth of microbes during the chilled storage of Pacific white shrimp. Copyright © 2012 Society of Chemical Industry     

1- 甲基环丙烯和二氧化氯对新疆蟠桃保鲜效果的研究

以新疆蟠桃为试材,于室温(23～25℃)和冷藏(4～5℃)贮藏条件下,分别用1.0μl/L 1- 甲基环丙烯(1-MCP)、1.0μl/L ClO2 及1.0μl/L 1-MCP+1.0μl/L ClO2 相结合的方法对蟠桃进行熏蒸处理。结果表明：两种条件下,三组处理均能明显抑制蟠桃乙烯释放量和呼吸速率,延缓蟠桃果实硬度、VC 含量和可滴定酸的下降;减少腐烂率;其中用1-MCP+ ClO2 处理的抑制效果优于1-MCP 和ClO2 单独处理;且低温加贮前1-MCP+ ClO2 处理更能有效地保持蟠桃的品质,延长保鲜期。     

Inhibition of melanosis formation in Pacific white shrimp by the extract of lead (Leucaena leucocephala) seed

Lead (Leucaena leucocephala) seed extract was prepared using distilled water as a medium. An extraction yield of 26.16 g/100 g of seed was obtained after extraction at room temperature for 12 h. Total phenolic and mimosine contents in the lead seed extract powder (LSEP) were 17.4 g GAE/100 g and 8.8 g/100 g, respectively. LSEP at different concentrations (0.05%, 0.1%, 0.25%, 0.5%, and 1%, w/v) showed inhibitory activity towards polyphenoloxidase (PPO) of Pacific white shrimp in a dose dependent manner. When the whole Pacific white shrimp were treated with 0.25% and 0.5% (w/v) LSEP, the shrimp treated with 0.5% LSEP had the lower melanosis score throughout the storage of 12 days and showed a higher score for colour and odour, as well as overall likeness, compared with the control (without treatment) and 1.25% sodium metabisulphite treated samples at day 12 (P < 0.05). Meat of shrimps treated with LSEP at both levels had the increase in mimosine content up to 8 days, suggesting the migration of mimosine into shrimp muscle during extended storage. Therefore, 0.5% LSEP can be used as a novel melanosis inhibitor for Pacific white shrimp.     

焦亚硫酸钠在虾类黑变控制中的应用研究

目的 探究焦亚硫酸钠预防鹰爪糙对虾黑变的最佳条件。方法 以鹰爪糙对虾为研究对象, 采用蒸馏法检测经焦亚硫酸钠处理后的对虾中SO2残留量及其在冷藏过程中的变化规律, 采用感官评分法进行防黑效果评价。结果 在符合国家标准限量(即SO2残留量不超过0.1 g/kg)前提下, 适宜浓度的焦亚硫酸钠溶液处理可以有效延缓鹰爪糙对虾的黑变, 且焦亚硫酸钠主要在贮藏前期起到延缓黑变的作用。其中, 3.0 g/L焦亚硫酸钠溶液浸泡对虾4 min可以有效延缓对虾黑变开始时间, 降低黑变程度。5.0 g/L焦亚硫酸钠溶液浸泡对虾30 s, 在贮藏前96 h内的黑变抑制效果更为明显。尽管对虾经该浓度的焦亚硫酸钠溶液处理后, 虾体内的SO2残留量略高于国标限量, 但SO2在贮藏过程中含量会发生减少, 贮藏12 h时即降至国标限量以下。结论 3.0 g/L焦亚硫酸钠溶液浸泡对虾4 min或5.0 g/L焦亚硫酸钠溶液浸泡对虾30 s, 两种处理工艺均可显著抑制鹰爪糙对虾贮藏过程中的黑变。从防黑变效果来看, 焦亚硫酸钠高浓度、短时间处理组的防黑变效果更优。     

水杨酸处理对板栗冷藏后货架期生理的影响

为探索水杨酸(SA)处理对板栗冷藏后货架期生理的影响机制,以“镇安”红栗为试材,采用不同浓度(1、3.5、7.5mmol/L)水杨酸处理10h,于(0 ± 1)℃、相对湿度65%～80% 条件下冷藏220d 后取出置于室温(温度17～26℃、相对湿度37%～46%)环境中,每隔3d 测定栗果腐烂率、呼吸强度、含水量、保护酶(SOD、CAT 和POD)活性及丙二醛(MDA)含量变化。结果表明：SA 处理可极显著抑制板栗货架期腐烂的发生,有效推迟呼吸峰的出现时间。1mmol/L 和3.5mmol/L SA 处理有利于保持栗果的水分含量,抑制了MDA 含量的增加。3.5mmol/L SA处理提高了货架后期SOD 活性,推迟了CAT 活性高峰的出现时间,并使POD 活性始终维持在较高水平。研究表明,采用1～3.5mmol/L SA 处理可使栗果在货架期保持较好的生理性状。     

Retardation of quality changes of Pacific white shrimp by green tea extract treatment and modified atmosphere packaging during refrigerated storage

The effect of modified atmosphere packaging (MAP) on the quality changes of Pacific white shrimp (Litopenaeus vannamei) treated with or without green tea extract (1 g/L; GTE) in combination with or without ascorbic acid (0.05 g/L; AA) during refrigerated storage of 10 days was investigated. Shrimp without treatment stored under MAP had lowered psychrotrophic bacteria, enterobacteriaceae and H₂S-producing bacteria count (P < 0.05) but similar lactic acid bacteria count (P > 0.05), in comparison with shrimp stored in air (control). The coincidental lowered rate of increase in pH, total volatile base (TVB) content and thiobarbituric acid reactive substances (TBARS) were obtained in shrimp stored under MAP (P < 0.05). However, MAP slightly lowered melanosis formation and improved likeness score to some extent. When shrimp were treated with GTE and stored under MAP, the lower microbiological and chemical changes as well as the lowest melanosis formation were observed, compared to shrimp kept under MAP without treatment and the control (P < 0.05). GTE treatment in combination with MAP could retard chemical changes and melanosis formation, regardless of AA incorporation (P > 0.05). Nevertheless, GTE in combination with AA had higher inhibition on microbial growth and yielded the shrimp with higher likeness, compared with the other treatments (P < 0.05). Therefore, shrimp treated with GTE in combination with AA prior to MAP had the lowest losses in quality during refrigerated storage.     

青鱼片冰温贮藏研究

将青鱼片分别放在(－ 0.8 ± 0.2)、(－ 2.0 ± 1.0)℃和(4.0 ± 1.5)℃的环境下贮藏,定期取出测定其感官、微生物和理化指标。贮藏期末,3 种贮藏条件下的样品菌落总数分别为1.17 × 106(第11 天)、1.12 × 106CFU/g(第8 天)和1.2 × 106CFU/g(第5 天);TVB-N 值分别为24.95(第20 天)、20.03mg/100g(第15 天)和20.39mg/100g(第12 天);pH值分别为6.96(第12 天)、6.59(第7 天)和6.73(第8 天)。结果表明,青鱼片在冷藏和微冻条件下分别在实验的第5 天和第8 天时已接近腐败,而在冰温贮藏的青鱼片在第11 天时才接近腐败。