发酵牛肉调味基料替代亚硝酸盐在红肠中的应用

在传统调味基料制备工艺基础上,增加微生物发酵环节制成发酵牛肉调味基料(Fermented beef flavor,FBF),将其按照不同添加比例应用于红肠的加工中,设计5组试验:阴性对照NC组(不添加亚硝酸盐)、阳性对照PC组(添加亚硝酸盐),分别添加2%、6%和10%发酵牛肉调味基料的样品组制成红肠,真空包装后,20 ℃条件下贮藏,在贮藏过程中对其进行品质评价。结果表明:发酵牛肉调味基料对红肠除具有明显提高风味作用(气味和滋味得分均不低于NC组)外,还起到良好的发色和抗氧化作用,添加发酵牛肉调味基料的试验组红肠的红度值与PC组无显著差异,当其添加量为2%时,红肠在贮藏过程中的TBARs值始终低于1.0 mg/kg,具有较强的抗氧化性。微生物多样性分析结果发现,发酵牛肉调味基料的添加对红肠中的优势腐败菌属(葡萄球菌属)具有明显抑制作用,其货架期比NC组明显延长,与PC组的保质期相当。可见,FBF具有应用于红肠中替代亚硝酸盐的潜力。     

低聚木糖的模拟移动床色谱分离研究

研究了用模拟移动床色谱分离高含量低聚木糖的工艺。首先通过单柱固定床实验来选择适合低聚木糖分离的固定相,比较了不同类型的离子交换树脂对低聚木糖和单糖混合液的分离度和分离效率．筛选出DIAION—UBK530Na树脂为合适的分离介质;然后运用真实移动床模型,近似确立模拟移动床色谱分离工艺的初始操作参数．在理论分离原理的指导下,优化分离条件,在阀切换时间为300s、进料流量和洗脱流量分别为3．5mL／min和5ml/min、提取液和提余液流量分别为3．8mL／min和4．7mL／min、同时循环流量控制在8．9mL／min的条件下．使分离后的低聚木糖、单糖纯度均在90％以上,收率分别达到91．55％和92．18％。     

发酵牛肉调味基料在牛肉饼中的应用效果

冷冻牛骨肉末经热-压浸提、酶解、发酵和美拉德反应后制成发酵牛肉调味基料（fermented beef flavoring,FBF）,以新鲜牛前肩肉为原料,加入不同比例腌制剂制成牛肉饼,分别为阴性对照（negative control,NC）组（既不添加NaNO2又不添加FBF）、阳性对照（positive control,PC）组（添加不同比例的NaNO2）及实验组。对牛肉饼进行感官评价后于20 ℃条件下贮藏,测定贮藏期间牛肉饼的红度值（a*）、pH值、硫代巴比妥酸反应物（thiobarbituric acid reactive substance,TBARs）值及亚硝酸盐残留量。结果表明：与NC组相比,PC组和实验组牛肉饼色泽红润,口感香嫩,风味得到明显改善;只添加FBF的实验组牛肉饼a*较高,TBARs值和亚硝酸盐残留量较低;同时添加NaNO2和FBF的牛肉饼口感、色泽及风味等品质均有所提高,且20 g/kg FBF和0.05 g/kg NaNO2复配制成的牛肉饼品质最好。     

预处理方式对甘薯变温压差膨化干燥产品品质的影响

为研究预处理方式对甘薯变温压差膨化干燥的影响,以甘薯为原料,探讨膨化初始含水量、糖煮处理和冻融处理对甘薯膨化干燥产品硬度、表观密度和感官等的影响。结果表明:甘薯膨化初始含水量为75%～80%,用40%麦芽糖浆液煮沸处理2min,-18℃下冷冻处理12h再室温(20℃)自然解冻,在膨化温度为100～105℃、抽真空干燥温度75～80℃条件下所制备的甘薯膨化产品具有良好的色泽和酥脆性。试验表明运用糖煮和冻融预处理可明显改善甘薯膨化干燥产品的酥脆性和色泽。     

Rosemary as antioxidant in pressure processed chicken during subsequent cooking as evaluated by electron spin resonance spectroscopy

The potential of rosemary (Rosmarinus officinalis L.) to inhibiting lipid oxidation in minced chicken breast and thigh muscle processed at 600 MPa for 10 min during subsequent heat treatment was investigated using electron spin resonance (ESR) spectroscopy and electrochemical detection of oxygen consumption. Chicken breast cooked at 95 °C was found to have significantly higher rate of formation of free radicals and oxygen consumption rate than the samples cooked at 70 °C and 120 °C and this intermediate cooking temperature was used to evaluate the effect of pressure on oxidation during subsequent cooking. Rosemary was found effective in retarding lipid oxidation since the pressurized, minced chicken breast and thigh with rosemary added showed lower rate of oxygen consumption and lower tendency of free radical formation following heat treatment than the samples without rosemary. Pressurized chicken thigh showed a higher susceptibility to oxidation than chicken breast upon subsequent heat treatment. Oxidation in pressurized and subsequently heat-treated chicken breast was from a higher tendency of radical formation concluded to be in an earlier phase of oxidation compared to thigh subjected to the same treatment.Industrial relevanceHigh-pressure processing has a great potential for microbial control of raw chicken meat as a “fresh” chill-stored, convenience product for wok cooking. While raw chicken meat is oxidatively stable, high-pressure treatment at 600 MPa and above induces lipid oxidation resulting in off-flavors during subsequent cooking. Addition of 0.1% dried rosemary to minced chicken thighs or breasts prior to high-pressure processing inhibit lipid oxidation during subsequent cooking and could form the basis for product development.     

Physicochemical properties and structure of starches from Chinese rice cultivars

Starches from 10 different non-waxy rice cultivars in China were isolated and investigated for their physicochemical properties including the swelling power, solubility, syneresis, thermal, rheological and textural properties, and structure. The range of amylose content in 10 rice starches was between 18.1 and 31.6%. The branch chain length distribution of amylopectin revealed that the proportions of short (DP6–11), medium (DP12–17), and longer chains (DP18–23) were 4.6–11.1%, 47.0–51.6% and 25.3–31.8%, respectively. The relationships between different properties of rice starches were determined using Pearson correlation analysis. Amylose content was negatively correlated to swelling power (r = ?0.632, p ≤ 0.05) and positively correlated to gel hardness (r = 0.776, p ≤ 0.01). The percentage of short chains (DP6–11) was negatively related to the transition temperatures (T_o, T_p and T_c), T_oG′ and T_G′max, while the percentage of medium chains (DP12–23) was positively related. Various branch chain length amylopectins played different roles in rheological behavior of starch dispersions. The percentage of short chains (DP6–11) was positively correlated to G′ and G″(r = 0.832 and r = 0.775, respectively, p ≤ 0.01), and negatively correlated to tanδ peak (r = ?0.717, p ≤ 0.05). However, the percentage of longer chains (DP18–23) showed a negative relation with G′ and G″ (r = ?0.794, p ≤ 0.01; r = ?0.741, p ≤ 0.05), and a positive relation with tanδ peak (r = 0.668, p ≤ 0.05).     

Starch from hull-less barley: I. Granule morphology,composition and amylopectin structure

Starch was extracted from 10 hull-less barley (HB) genotypes [waxy (CDC Candle, CDC Alamo, SB 94912, and SB 94917), normal amylose (Phoenix, CDC Dawn, SR 93102, and SB 94860), and high amylose (SB 94893 and SB 94897)]. Starch content ranged from 56 to 65%. The purity of the isolated starches was greater than 96%. Average starch yield and extraction efficiency were 44 and 71%, respectively. The starches from all genotypes consisted of a mixture of large lenticular and small irregularly shaped granules. The granules of most starches were intact, whereas in others (SB 94917, SR 93102, and SB 94860) they were compound (clustered). The proportions of small (diameter⩽10 μm) and large granules (diameter>10 μm), by total number and by total weight differed among genotypes. Bound lipid content was positively correlated (r=0.92, P<0.01) with total amylose content. Free and bound lipid contents ranged from 0.1–0.3% and 0.3–1.7%, respectively. The apparent and total amylose contents ranged from 0–39% and 0–45%, respectively. The amounts of amylose complexed with native lipids (total amylose–apparent amylose) ranged from 0.5 to 7.8%. The proportion of small granules was correlated with total amylose content (r=0.59, P<0.1). However, the average granule diameter was negatively correlated (r=−0.65, P<0.05) with total amylose content. The debranched amylopectins of all starches exhibited the highest peak in the MALDI-MS spectrum at DP 12. The average chain length (CL) and degree of branching ranged from 17.6–22.7% and 4.4–5.5%, respectively. The short (DP 5-17) and long (DP⩾35) chains ranged from 58.2–59.1% and 3.0–12.8%, respectively. The study showed that amylose/amylopectin ratio and amylopectin branch chain length have high correlation with granule size and size distribution in this set of barley genotypes.     

红枣山楂果丹皮和果糕的制作及品质评价

以红枣、山楂为主要原料制作红枣山楂复合产品。确定了红枣山楂复合(简称复合)果丹皮的最佳工艺为:红枣与山楂的配比为3:1,料水比为2:1,沸水煮10min,果浆铺片厚度为6～7mm,温度控制在60～70℃,烘8～9h,切片,包装。复合果糕的最佳工艺为:红枣和山楂的配比为1:1.2,料水比为2:1,沸水煮15min,加入1%琼脂和10%木糖醇,冷却凝固成型。探讨分析了复合产品的感官评价和基本理化指标,并与市售产品进行对照。结果显示:复合果丹皮的总糖含量比市售山楂果丹皮降低了33.3%,复合果糕的总糖含量比市售山楂糕降低了42.9%。复合果丹皮和果糕分别与市售产品的感官评价和质构分析对照显示,复合产品在感官上与市售产品相近。结果说明红枣山楂复合产品可行,具有实际意义。     

壳聚糖/CMC复合涂膜处理对柑橘果实采后品质的影响

流延法制备壳聚糖单层膜及羧甲基纤维素钠/壳聚糖复合膜,并测定膜机械性能、微观结构和水蒸气透过性等对其进行表征;以春香和柠檬两个柑橘品种为试材,研究壳聚糖单层涂膜及羧甲基纤维素钠/壳聚糖自组装复合涂膜对两种柑橘果实（春香,柠檬）采后货架期品质的影响。结果发现：复合膜的水蒸气透过性显著（p<0.05）高于单层膜,为壳聚糖单层膜的1.74倍;且维持良好的力学性能及微观结构。应用于柑橘采后保鲜,发现涂膜可提高柑橘果亮度,抑制抗坏血酸氧化,减少硬度降低。涂膜处理可减少柑橘果实表面气孔数量,降低贮藏期间柑橘果实失重率,贮藏20 d处理组失重率均在7.5%以下;且涂膜延缓了柑橘可滴定酸含量的下降。与单层涂膜相比,羧甲基纤维素钠/壳聚糖自组装复合涂膜可显著（p<0.05）提高春香、柠檬硬度及抗坏血酸含量。经20 d贮藏,复合涂膜组的春香及柠檬硬度分别是对照组的1.15倍、1.23倍。复合膜证实了静电吸附自组装形成的多糖基膜具有维持柑橘采后品质的潜力,为开展不同柑橘品种生物涂膜保鲜研究提供参考。