基于神经网络法优化即食皱纹盘鲍栅栏模式

以栅栏技术理论为指导,采用神经网络模型优化不同栅栏模式对即食鲍鱼（Haliotis discus hannai Ino）产品的防腐保鲜效果。通过研究几个栅栏因子（烘干后产品的水分活度（aw）、乳酸链球菌素（Nisin）、乳酸钠的添加量以及杀菌温度）组合得到的不同栅栏模式的防腐保鲜效果以及对产品品质的影响,以菌落总数及感官评分作为响应值建立神经网络模型并进行优化。结果表明：产品最适栅栏模式为：aw为0.92,Nisin、乳酸钠添加量分别为0.39 g/kg、1.6%,杀菌温度89 ℃,此栅栏模式防腐保鲜效果好,且能较好地保持产品的质地和风味。     

烧鸡综合保鲜技术研究

根据栅栏因子保鲜理论,采用多种栅栏因子科学合理的组合,对烧鸡进行了综合保鲜研究。结果表明:复合防腐剂(Nisin0.05%、溶菌酶0.05%、乳酸钠2%和双乙酸钠1%)+真空包装+水浴热处理(85～90℃水浴杀菌30min,流水冷却30min)的综合保鲜技术可使烧鸡在常温下(15～20℃)贮藏60d。     

南美白对虾温和加工即食制品栅栏因子的优化设置

研究并提高南美白对虾即食加工制品品质和贮藏性。采用正交实验和感官评价等方法研究制品中4个主要的栅栏因子(水分活度、pH、热杀菌和添加剂)和各因子间的相互作用,并优化各因子的强度,得出4个主要的栅栏因子的较佳强度为Aw0.94、杀菌温度85～90℃和时间40min、Nisin100mg/kg、乳酸钠2.4%、pH5.8～5.9。因此运用栅栏技术能试制出较好保存南美白虾鲜美风味的制品并提高其贮藏性,为栅栏技术在食品工业更广泛应用提供帮助。     

响应面法优化冷鲜肉复合保鲜剂的研究

冷鲜肉中原始菌落总数对其储藏过程中品质的变化有显著影响。根据栅栏因子理论选取了4种栅栏因子温度、pH值、抗菌成分与保水因子研究冷鲜肉的保鲜,研究了乳酸、二氧化氯、多聚磷酸盐复配的保鲜剂。单因素试验表明乳酸浓度在1.5%、二氧化氯在40 mg/kg时抑菌效果显著。采用响应面法,通过中心组合设计试验,以菌落总数的降低率为评价指标,筛选了最佳组合为乳酸为1.4%、二氧化氯为18.7 mg/kg、多聚磷酸盐为4%,且降菌率为90.25%。由此可见,上述4种栅栏因子能很好地起到降低冷鲜肉的菌落总数,起到防腐保鲜的作用。     

冷藏调理即食鲨鱼皮保鲜技术研究

本文以鲨鱼皮为原料,将栅栏防腐技术应用于冷藏调理即食鲨鱼皮的保鲜.单因素试验选择并确定冷藏调理即食鲨鱼皮的适宜前期减菌技术与抑菌保鲜剂及其浓度范围;采用L9(34)正交试验设计,以菌落总数和挥发性盐基氮(TVB-N)为衡量指标,优化抑菌保鲜液的配比.研究结果表明:臭氧杀菌技术能有效实现冷藏调理即食鲨鱼皮的前期减菌作用,在臭氧浓度固定为500 mg/kg的条件下,作用25 min时,前期减菌效果明显.优化后的冷藏调理即食鲨鱼皮抑菌保鲜液的配比为,山梨酸钾0.060 g·kg-1,乳酸链球菌素(Nisin)0.4 g·kg-1,保鲜液pH≤4.5;在此条件下,产品的保鲜效果最好,在0℃～4℃条件下,可防腐保鲜60 d.     

栅栏技术在调理食品中的应用研究

利用远红外线脱水、紫外线杀菌、高温处理、低温冷藏作为栅栏因子,作用于新型调理食品--土豆烧排骨的加工保藏过程。贮藏期内通过对样品的感官检测及微生物测定,确定出各栅栏因子的作用效果及最佳强度。结果表明采用1500W远红外线95℃、20min,235W紫外线25min,78℃、25min巴氏杀菌,0～4℃低温冷藏作用于该产品的加工保藏过程,能杀灭有害菌,而且不会对产品的风味和口感造成不良影响。     

即食调味鱼块加工栅栏因子优化

为了获得即食调味鱼块温和加工条件,最大限度地延长产品货架期,采用Plackett-Burman设计和中心组合设计优化了即食调味鱼块加工栅栏因子,建立了科学的数学模型,获得最优栅栏因子组合为乳链球菌素0.6g/kg,乳酸钠1.0g/kg,山梨酸钾0.6g/kg,白醋0.8%,复合磷酸盐8g/kg,复合香辛料1%,微波功率880W,微波作用时间10min。     

低糖脆梅加工中栅栏技术的研究

以ClO_2的浓度、ClO_2的浸泡时间、山梨酸钾的添加量、650W微波的处理时间为对象进行栅栏技术研究,研究发现4个因子对杀菌效果均有极显著的影响,其中以微波处理时间为最主要影响因素,其次为ClO_2浓度,然后为山梨酸钾添加量,最后是ClO_2的浸泡时间。栅栏因子结合应用的效果优于单个因子,其适宜的参数为:脱硫后用40mg/L ClO_2浸泡梅果10min,渗糖时在糖液中添加0.65g/kg的山梨酸钾,渗糖包装后以650W的微波处理75s。     

紫色甘薯泥的生产工艺研究

研究了紫色甘薯泥的制备工艺及其产品的质量控制,重点研究其护色及酶解关键技术.实验结果表明,在亚硫酸氢钠400mg/kg、抗坏血酸300mg/kg、柠檬酸1400mg/kg的混合护色液中浸泡10min,护色效果最佳;在温度50℃下添加1.5%(1:3)的复合酶(α-淀粉酶与糖化酶)水解90min,所得产品呈均匀泥状,具有固有的紫色色泽、滋味和气味;甜味适中,口感细腻滑爽.     

栅栏因子对高水分即食牡蛎产品抑菌效果的影响

以栅栏效应理论为指导,研究不同栅栏因子对高水分即食牡蛎产品的抑菌效果。通过合理设置多个强度缓和的栅栏因子,即杀菌温度、酸度(pH 值)、水分活度、包装方式,通过它们之间的交互作用,形成有效防止制品腐败变质的栅栏,开发出感官品质良好的高水分半干牡蛎食品。结果表明,各栅栏因子在不同强度下的抑菌效果不同,产品最适抑菌模式和强度为：在60℃烘烤2h,采用10% 醋酸加入量调节产品pH 值在5.5 左右,在调味时添加16% 的白砂糖调节产品的水分活度在0.90 左右,杀菌强度为100℃、30min,并且采用真空包装。研制出的高水分即食牡蛎产品,较好地保持了产品的质地和风味。     

应用二氧化氯保鲜烧鸡

探讨天然黄色素对熟肉制品的防腐作用.用不同浓度黄色素水溶液及加热煮沸、晾凉后的黄色素水溶液处理熟驴肉块,35℃培养自然生菌72h,分别统计霉斑数、霉菌孢子体数目,计算病情指数.油菜花黄色素溶液浓度在0.05%以上对熟驴肉具有显著的防腐性,但经加热煮沸后防腐作用降低.     

气体射流冲击北京烤鸭鸭皮的色泽和酥脆性

研究加工条件和保藏条件对北京烤鸭鸭皮色泽和酥脆性的影响.以气体射流冲击的北京烤鸭为研究对象,研究了烤制温度、烤制时间和饴糖溶液浓度等加工条件对烤鸭鸭皮色泽的影响,以及温度和含水率等对烤鸭鸭皮酥脆性的影响.结果表明,烤制温度、烤制时间和饴糖溶液浓度对北京烤鸭色泽影响显著.在实验条件范围内,随着烤制温度的上升,烤制时间的延长,烤鸭鸭皮色泽亮度值(L*)逐渐下降,红绿值(a*)上升,黄蓝值(b*)上升,在烤制温度190℃、烤制时间45min、水和饴糖比为12∶1 (m/m)时鸭皮色泽较佳.鸭皮的酥脆性与鸭皮的温度和含水率相关,温度低于鸭油凝固温度时,鸭皮的色泽变浅,酥脆性降低;随着含水率的增大,鸭皮酥脆降低.     

Determination of phenols in coffee

The structure and quantity of phenols, occurring in two different roasted Robusta coffees and in four samples of roast coffee, were investigated. Identification and quantification were carried out after special extraction procedures and clean-up methods by gas chromatography/mass spectrometry. The quantities of 35 phenols investigated ranged from below 0.1 mg/kg to more than 1000 mg/kg. Sixteen phenols were identified in coffee for the first time.     

Cooking influences on the palatability of roasts from the beef hip

Two experiments were undertaken to obtain factual information to serve as a basis for guidance to consumers regarding optimal preparation and cooking procedures to be utilized with beef round cuts. Experiment I compared low temperature, dry beef cookery with moist beef cookery with a dry heat finish on five different roast cuts from the beef hip. Experiment II compared four different cookery methods for their influence on palatability attributes and cooking properties of eye of round (semitendinosus) roasts. Based upon results from Experiment I, low temperature, dry heat cookery should be recommended to consumers to improve the palatability of roasts from the beef hip, providing consumers are prepared to expend twice as long to prepare roast cuts. Results from Experiment II clearly indicate method C [high temperature, covered (oven turned on to 260 °C, with 250 ml of water added after 30 min)] should not be the method of choice. Although any of the other three methods could be recommended to provide a relatively palatable product, method D [high temperature initially, subsequently reduced, uncovered (roast brushed with 5 ml of Kitchen Bouquet™, placed into a cold oven turned on to 260 °C, with 250 ml of water added after 30 min and the oven temperature reduced to 140 °C)] appears to provide a more acceptable product based upon tenderness, particularly initial tenderness, than methods A [low temperature, dry heat (140 °C oven, uncovered with no moisture added)] and B [low temperature with moisture added (160 °C oven, uncovered with 250 ml of water added initially and 50 ml of water added every 30 minutes)]. In addition 46.4 min/kg less time was required to prepare roasts with method D than with method A. Consequently, the method of choice for recommendation to consumers is method D.     

Compositional and Mechanical Properties of Peanuts Roasted to Equivalent Colors using Different Time/Temperature Combinations

Abstract: Peanuts in North America and Europe are primarily consumed after dry roasting. Standard industry practice is to roast peanuts to a specific surface color (Hunter L‐value) for a given application; however, equivalent surface colors can be attained using different roast temperature/time combinations, which could affect product quality. To investigate this potential, runner peanuts from a single lot were systematically roasted using 5 roast temperatures (147, 157, 167, 177, and 187 °C) and to Hunter L‐values of 53 ± 1, 48.5 ± 1, and 43 ± 1, corresponding to light, medium, and dark roasts, respectively. Moisture contents (MC) ranged from 0.41% to 1.70% after roasting. At equivalent roast temperatures, MC decreased as peanuts became darker; however, for a given color, MC decreased with decreasing roast temperature due to longer roast times required for specified color formation. Initial total tocopherol contents of expressed oils ranged from 164 to 559 μg/g oil. Peanuts roasted at lower temperatures and darker colors had higher tocopherol contents. Glucose content was roast color and temperature dependent, while fructose was only temperature dependent. Soluble protein was lower at darker roast colors, and when averaged across temperatures, was highest when samples were roasted at 187 °C. Lysine content decreased with increasing roast color but was not dependent on temperature. MC strongly correlated with several components including tocopherols (R² = 0.67), soluble protein (R² = 0.80), and peak force upon compression (R² = 0.64). The variation in characteristics related to roast conditions is sufficient to suggest influences on final product shelf life and consumer acceptability. Practical Application: Peanuts are typically dry roasted to a specified surface color for a given food application; however, it is possible to obtain equivalent colors using different temperatures. This simple observation led to the overall goal of this research which was to determine if peanuts roasted to equivalent surface colors using different temperatures are equivalent from a quality perspective. Several compositional and textural measurements important to product quality differed based on the temperature used to achieve a given roast color. Overall, this study suggests there is good potential to optimize peanut quality by simply adjusting the time/temperature profiles during roasting.     

体外模拟腌肉制品中亚硝胺形成条件及机理的研究

试验主要是在试管里模拟腌肉环境,意在找出影响亚硝胺形成的主要因素。试验总结出熟化温度、熟化时间、肉的pH值是影响亚硝胺形成的几个外部因素,其中温度是最主要因素,其次是熟化时间,而pH值为不重要因素。     

不同工艺即食烤鱼多环芳烃检测方法及变化研究

目的:建立即食烤鱼16种多环芳烃（Polycyclic aromatic hydrocarbons, PAHs）检测方法,分析不同工艺对烤鱼PAHs种类及含量的影响。方法:样品经正己烷提取,采用固相萃取柱净化,二氯甲烷洗脱,高效液相色谱法测定。结果:16种PAH_S相关系数为0.9993~0.9998,检出限为0.20~2.50 μg/kg;加标回收率为64.25%~122.8%,相对标准偏差为1.38%~7.13%。在碳烤、油炸、电烤三种不同熟化方式下,烤鱼中调味料的添加可减少PAHs的生成量;烤鱼中PAHs的种类和含量为碳烤>油炸>电烤,样品中萘、苊烯、菲和芘检出含量较高,碳烤样品PAHs总量高达58.74 μg/kg,明显高于油炸和电烤样品组;熟化时间和温度对烤鱼PAHs种类及含量均有影响,随油炸时间延长、油炸温度增高,样品PAHs检出种类和含量增加明显,其中,萘、苊烯、菲、荧蒽和芘含量增高达3~5倍;随电烤时间和温度的增加,样品中PAHs种类增多,PAHs总量亦提高;通过风险评估,烤鱼加热时间控制在6 min,温度200 ℃以内,摄入频率小于每月2次,食用风险低。结论:建立了烤鱼中16种PAHs的检测方法;进行了不同工艺烤鱼样品中PAHs的种类、含量变化分析及风险评估,为即食烤鱼熟化工艺选择提供依据。     

Fabricated Beef Product: Effect of Handling Conditions on Microbiological, Chemical, and Sensory Properties

Total microbial count was not adversely affected by lowering the holding temperature of fabricated beef roast from 60°C to 54°C or by 12 hr holding time. If a reduction in holding temperature is anticipated, then initial roast contamination and sanitation of the food facility are of critical importance. A stabilizing period of 20 min at room temperature (～23°C) did not decrease yield, but caused a slight lowering of sensory scores. Tenderness was more acceptable in product held at 54°C compared to 60°C. In general, all sensory evaluation ratings were slightly lower with increased holding time.     

Influence of water activity,temperature and incubation time on the simultaneous production of deoxynivalenol and zearalenone in corn (Zea mays) by Fusarium graminearum

The production of deoxynivalenol and zearalenone by Fusarium graminearum was studied under different culture conditions (water activity, temperature and incubation time). The maximum levels of both toxins were obtained at the 35th day of incubation, the zearalenone level being much higher than the deoxynivalenol. The culture conditions that gave higher yields of deoxynivalenol were at 22 and at 28 °C (6.0 and 5.5 mg/kg ), after 35 days. At an incubation temperature of 28 °C 16 days, followed by 12 °C, for the same time, the production was low (1.1 mg/kg). The highest level of zearalenone was obtained at 28 °C for 16 days, followed by incubation at 12 °C (36.7mg/kg) at the 35th day. When the temperature was constant at 28 °C, the zearalenone production was lower (3.0 mg/kg) than when incubated at 22 °C (12.3 mg/kg), at the 35th day. Fusarium graminearum did not produce deoxynivalenol and zearalenone at 37 °C.     

Ochratoxin A in Brazilian roasted and instant coffees

Thirty-four samples of roast and ground coffee, 14 samples of instant coffee and two samples of decaffeinated instant coffee were collected in markets and supermarkets in the city of Campinas, Brazil, and analysed for ochratoxin A using immunoaffinity columns for clean-up and HPLC with fluorescence detection for quantification. The limit of detection was 0.2 ng/g ochratoxin A. Twenty-three samples of ground and roast coffee were found to be contaminated with the toxin at levels ranging between 0.3 and 6.5 ng/g. The average concentration in all 34 samples was 0.9 ng/g. All samples of instant coffee contained ochratoxin A at levels ranging from 0.5 to 5.1 ng/g, with an average figure of 2.2 ng/g. Roast and ground coffee is the type of coffee most used by Brazilians for the preparation of the beverage. Considering that an average Brazilian adult takes five cups of coffee per day, which corresponds to 30 g of roast and ground coffee, the probable daily intake of ochratoxin A by a 70 kg adult would be 0.4 ng/kg bw, which is far below the current Provisional Tolerable Daily Intake of 14 ng/kg bw for ochratoxin A as set by the Codex Alimentarius. To study the transfer of ochratoxin A into coffee brew, the beverage was prepared by two methods: (a) the drip method and (b) the Brazilian country style method. No significant difference was observed between the two methods in terms of extraction of the toxin using five contaminated samples containing between 0.8 and 6.5 ng/g ochratoxin A. The drip method extracted 86 +/- 15% and the Brazilian country style 74 +/- 20% of the ochratoxin A initially present in the roast and ground coffee.