不同包装容器米糠油的货架期评价研究

针对消费者质疑市场上米糠油产品标注保质期为18个月的现状,选择了300 m L玻璃瓶、300m L PET瓶和5 000 m L PET瓶3种小包装米糠油(未添加抗氧化剂)进行货架期(15~20℃)试验,并分析了Schaal烘箱法和Rancimat法在预测米糠油货架期方面的准确性。结果表明:水分及挥发物含量、酸值和过氧化值均随储藏时间的延长而增大;300 m L玻璃瓶装米糠油品质最好,货架期可达15.5个月,300 m L PET瓶和5 000 m L PET瓶装米糠油品质其次,货架期分别为10.5个月和7.4个月,但三者均未达到18个月;Schaal烘箱法与Rancimat法在预测米糠油货架期方面基本无差异,分别为6.9~10.3个月、6.5~9.2个月,两法所预测的货架期与PET瓶装的米糠油货架期接近。     

不同脱酸工艺对红花籽油储藏品质的影响

为了选择合适的脱酸工艺,提高红花籽油的储藏品质,以脱胶红花籽油为原料,采用碱炼脱酸和超声波辅助乙醇萃取(UAEE)脱酸工艺制备脱酸红花籽油,并采用Schaal烘箱法进行加速氧化试验,比较加速氧化期间脱酸红花籽油的理化指标(酸值、过氧化值、p-茴香胺值)、脂质伴随物(α-生育酚、总酚、总甾醇)含量,以及体外抗氧化能力(DPPH、ABTS自由基清除能力),对比分析2种脱酸工艺对红花籽油储藏品质的影响,并预测货架期的差异。结果表明：随着储藏时间的延长,2种脱酸红花籽油的理化品质、脂质伴随物含量、体外抗氧化能力均呈下降趋势;与碱炼脱酸工艺相比,UAEE脱酸工艺制备的红花籽油储藏品质更优;2种脱酸红花籽油的氧化均符合一级氧化动力学反应,通过动力学方程预测20℃和25℃密封避光条件下,UAEE脱酸红花籽油的货架期分别约为28 d和27 d,而碱炼脱酸红花籽油的分别约为22 d和21 d。综上,与碱炼脱酸相比,UAEE脱酸能提升红花籽油的储藏品质,有利于延长红花籽油的货架期。     

糊辣牛肉在不同温度条件下的贮藏特性及其货架期预测

以糊辣牛肉为实验材料,研究其不同贮藏温度条件下的贮藏特性和贮藏期间各品质指标的Pearson相关系数,建立了货架期预测模型。结果表明:贮藏期间产品pH值先降后升,伴随着菌落总数、TVB-N值和TBA升高,感官品质和硬度下降;贮藏温度越低,产品品质保存越好,货架期越长;在5℃、15℃、25℃、37℃和45℃货架期分别为16.0 d、12.5 d、8.5 d、3.0 d和1.5 d;不同温度条件下菌落总数与感官品质、pH、TVB-N、TBA和硬度均呈极显著相关(p0.01);依据贮藏特性的动态变化,开发出多元回归模型、温度与货架期关系回归模型和tTVB-N、tTVB-N和tHardness动力学货架期模型。通过模型验证发现,温度与货架期关系模型能快速有效预测5℃~25℃范围内方便菜肴糊辣牛肉货架期,相对误差范围为0.29%~2.36%;5℃~37℃范围内多元回归模型预测效果较佳,相对误差范围为1.07%~7.89%;tTVB-N、tTVB-N和tHardnes动力学货架期模型预测效果较差。     

盒装巴氏奶货架期的快速预测

采用阻抗法进行盒装巴氏奶货架期预测,结果表明,巴氏奶货架期与细菌数对数值密切相关,在30℃、6h预培养下加样300,400μL及37℃、6h预培养下加样100－400μL进行阻抗测定,建立回归方程式均可快速准确地进行盒装巴氏奶货架期预测,整个预测过程耗时14－20h.     

超高压对峰甘板栗中主要微生物的影响及其货架期预测

为探讨超高压对真空包装峰甘板栗微生物及感官质量的影响及建立微生物生长模型预测其货架期,在16~18℃对真空包装峰甘板栗进行200 MPa(5、10、15 min)、300 MPa(5、10、15 min)、400 MPa(5、10、15 min)、500 MPa(5、10、15 min)超高压处理。样品处理后于4℃保藏60 d,每隔10 d取样分析,直至样品微生物数量达到安全卫生限值1 000 CFU/g及感官质量不可接受为止。结果表明,与空白对照组相比,超高压处理能显著降低峰甘板栗初始微生物数量,并对影响货架期的腐败微生物:大肠菌群、霉菌、酵母有显著抑制作用,抑制程度与压力(200~500 MPa)和处理时间(5~15 min)具有正相关性;试验中所建立的Gompertz模型能有效地拟合不同超高压处理峰甘板栗在货架期间菌落总数的动态变化,有效地评估峰甘板栗的货架寿命和贮藏安全性,500 MPa处理5、10、15 min均能够将峰甘板栗4℃贮藏微生物货架期从9 d延长至60 d以上;但结合感官质量评定结果,300 MPa处理15 min最佳可延长货架期至38 d。     

桦褐孔菌多酚对食用油脂的抗氧化效应研究

以花生油、大豆油和猪油为底物,采用烘箱贮藏法测定油脂的POV值,并对其货架期进行预测,研究桦褐孔菌多酚对食用油脂的抗氧化效果.结果表明,桦褐孔菌多酚对食用油脂具有较好的抗氧化效果,食用油脂在添加了桦褐孔菌多酚后,其货架期均得到延长,尤以花生油和猪油的效果最明显,其货架期分别由128d延长到224d,640d延长到986d.     

氮掺杂石墨烯修饰丝网印刷电极测量油脂氧化诱导时间

构建了一种氮掺杂石墨烯(NRG)修饰丝网印刷电极交流阻抗法测量油脂氧化诱导时间的新型测量体系。优化了电极组成和阻抗测量条件,研究了油脂阻抗值与过氧化值随时间的变化关系。结果表明:最优条件为导电碳浆配方为氧化石墨烯、碳纳米管、鳞片石墨粉和四乙氧基硅氧烷(TEOS)质量比为0. 1∶0. 1∶1∶2,NRG修饰量3μL,支持电解质为p H 7. 0的磷酸盐缓冲液,体积比1∶2的乙腈与磷酸盐缓冲液(pH 7. 0)为萃取剂,油和萃取剂体积比1∶1,流量1. 5 m L/min,测量频率(5～8)×10~5Hz。在最优条件下,萃取剂能较快速高效地萃取油脂氧化过程中产生的极性和弱极性氧化产物,所建立的测量体系能够灵敏地检测萃取相的阻抗值及其变化。由油脂氧化过程中阻抗值-时间曲线所得的氧化诱导时间,与由国标法所得的氧化诱导时间的相对偏差小于5%,F检验和t检验结果表明两种方法之间不存在系统误差。     

不同油脂对富含马铃薯泥的面包品质影响

在掌握面包制作工艺基础上,制作了富含马铃薯泥的面包,研究不同油脂对富含马铃薯泥的面包物理性质、贮藏性质和感官品质的影响。结果表明:添加油脂使富含马铃薯泥的面包样品的比容、硬度、弹性、贮藏性能和感官品质均有不同程度的提升;添加橄榄油的样品比容最大(5. 69 m L/g),添加黄油的样品硬度最小(247. 19 g),添加人造奶油的样品弹性最大(0. 96);添加油脂的样品的感官评分均高于90分,添加黄油的样品感官评分最高(97. 97分);贮藏5 d后,添加人造奶油的样品硬度最小(447. 49 g)、弹性最大(0. 78)、水分含量最高(19. 32%);相关性研究发现,富含马铃薯泥的面包的比容和硬度几乎与感官评定所有指标具有相关性,可以通过检测比容和硬度对富含马铃薯泥的面包感官品质进行预测。     

BHT的电化学性质研究

油脂在热、光、重金属和辐射等因素下,极易发生氧化而产生酸败,为此,需要在油脂中添加不同种类的抗氧化剂延缓氧化,达到延长货架期的目的。2,6-二丁基羟基甲苯（BHT）是油脂中常用的抗氧化剂。本文基于抗氧化剂BHT的介电性质,探讨了BHT的电化学行为。研究中以Nation修饰玻碳电极作为工作电极、以LiClO4乙腈溶液作为电解质,采用循环伏安扫描测定法（CSV）,从BHT的电化学性质方面对其抗氧化机理进行了阐述,且得到了在1．65×10^-5-1．65×10^4mol／L范围内BHT加入量与氧化峰电流呈良好的线性关系,以探讨建立一种新型的油脂中抗氧化剂添加量快速测定方法。     

速冻青稞鱼面贮运过程中货架期预测模型构建

通过对不同贮运温度下速冻青稞鱼面的感官、理化指标的变化分析,分别建立基于感官威布尔危害分析(Weibull Hazard Analysis,WHA)、化学动力学(Arrhenius)、BP神经网络(Back Propagation)的货架期预测模型,并验证结果。研究结果表明：在-18℃~25℃范围内,面条货架期随温度的升高逐渐缩短;根据国家标准确定速冻青稞鱼面在-18℃、-10℃、-5℃、0℃、5℃、10℃、25℃温度下货架期实际终点分别为94d、195d、100d、30d、24d、18d、3d;相关性分析显示,贮藏时间与TBA值呈极显著正相关,与POV值、pH值、感官评分相关性不显著。在-18℃、-10℃、-5℃、0℃、5℃、10℃、25℃温度下,基于感官评价指标的威布尔危害分析的货架期预测终点为296.21d 、206.89d、101.94d、29.92d、23.46d、19.15d、3.29d ,相对误差为0.27%~9.67%;基于TBA指标的Arrhenius方程,货架期预测终点为413.30d 、170.87d、101.05d、60.92d、37.40d、23.36d、6.26d,相对误差为1.05% ~108.62%。基于感官评价和理化指标(PH、TVB-N、TBA、POV)的BP神经网络模型货架期预测终点为281.45d 、190.07d、103.24d、31.46d、23.20d、17.17d、2.76d ,相对误差为4.60～7.96%。Weibull与BP神经网络预测模型性能较优,可用于速冻青稞鱼面的货架期终点预测。     

小茴香籽油包合物对泡菜发酵过程的影响

小茴香籽油是公认的抗菌剂,但因其低水溶性、强挥发性和刺鼻的气味限制了其在食品领域的应用。实验以β-环糊精包合小茴香籽油制得包合物,考察包合物作为天然抗菌剂对于泡菜保质期和品质的影响。在10℃发酵条件下,测定15d内添加不同包合物浓度(0.0%~1.0%)的泡菜pH、可滴定酸度、微生物变化和感官试验变化。结果表明,小茴香籽油包合物可延缓泡菜pH,可滴定酸度的变化速率,抑制总微生物、乳酸菌的生长,同时,结合感观分析结果,推荐0.5%浓度小茴香籽油包合物处理泡菜。     

Moisture sorption isotherms and thermodynamic properties of safflower seed using empirical and neural network models

Experimental work was conducted to obtain the adsorption isotherms of safflower seed using a semi static gravimetric method at 25, 40, and 60 °C over a water activity range from 0.11 to 0.94. Fourteen isotherm equations and multilayer artificial neural network approach were employed to analyze the experimental data. In order to evaluate the goodness of fit of each model determination coefficient, Chi Square and root mean square error were used. The Peleg (at 25 and 40 °C) and Osvin (at 60 °C) models were selected to best describe the sorption isotherms of safflower seed. Accordingly, the results showed that the predicted values of ANN model were more accurate than those predicted by nonlinear regression method. The adsorption monolayer moisture content was also determined using Brunauer, Emmett and Teller equation. The monolayer moisture content values were 0.028, 0.024, and 0.022 gH₂O/g solid at 25, 40, and 60 °C, and the corresponding constant values of the Brunauer, Emmett and Teller equation were found to be ?13.029, ?10.873, and ?17.255, respectively. The safflower seeds heat of sorption values was also found. The heat of sorption values was large at low moisture content and decreased with an increase in the moisture content, whereas the magnitudes increase with increases in temperature and could be well adjusted by an exponential relationship. The experimental data revealed that enthalpy-entropy compensation theory was satisfactorily applicable to the moisture sorption behavior of the safflower seed.     

刺梨果汁饮料的贮藏稳定性及其货架期预测

目的 提高刺梨果汁饮料的贮藏稳定性及评估其保质期。方法 刺梨果汁饮料经均质、微波杀菌等处理后于25 ℃贮藏30 d,探究加工工艺(均质时间、杀菌时间、稳定剂种类)对饮料理化性质的影响。根据主要活性成分的含量随贮藏时间及贮藏温度的变化,利用动力学方程和Arrhenius方程建立刺梨果汁饮料的货架期模型并预测其货架期。结果 当均质时间为3~5 min、微波杀菌时间2~4 min,添加0.1% l-卡拉胶时,刺梨果汁饮料的稳定性较好;贮藏试验显示,相比总黄酮含量,刺梨果汁饮料中Vc含量与贮藏时间相关性更高,且符合零级反应(R2> 0.900);根据Arrhenius方程预测出刺梨果汁饮料在4、25、45 ℃的货架期分别为226、126、78 d。验证试验表明,预测Vc含量与实测Vc含量之间的相对误差均低于10%。结论 适当的加工处理可提高刺梨果汁饮料的贮藏品质,延长其保质期。Arrhenius方程适合于刺梨果汁饮料品质及货架期的评估。     

Evaluation of the quality of olive oil using fatty acid profiles by direct infusion electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry is used to predict the olive oil quality according to European Union marketing standards. Samples were 1:50 diluted in an alkaline 85:15 (v/v) propanol/methanol mixture and directly infused into the electrospray ionization source of an ion trap mass spectrometer. The establishment of ratios of the peak abundances of the free fatty acids followed by linear discriminant analysis was employed to predict the olive oil quality grade. In addition, using multiple linear regression and partial least-squares regression, the percentages of extra virgin and virgin olive oils in binary mixtures were predicted with 5–11% average prediction errors.     

Polymer additive migration to foods - a direct comparison of experimental data and values calculated from migration models for high density polyethylene (HDPE)

To reduce the amount of compliance testing for food contact polymers the use of migration modelling has been proposed. This study was conducted to provide valid data for the independent evaluation of two such diffusion-based models using a range of different high density polyethylene (HDPE) polymers and plastics additives. Seventy-two experimental migration data have been obtained in triplicate and used to evaluate two Fickian-based migration models in the prediction of specific migration of four HDPE additives into olive oil. All tests were conducted using olive oil, representing the most severe case for fatty foods with test conditions of 2h at 70oC, 6h at 70oC, 10 days at 40oC representing short term exposures at high temperatures and room temperature storage. Predicted migration values were calculated by inserting the measured initial concentration of additive in the polymers (Cp,0) into the equations together with known variables such as additive molecular weight, temperature and exposure time. The results indicate that both models predict migration values into olive oil close to, or in excess of, the experimental results. The Piringer migration model, using the 'exact' calculations of the Migratest Lite program, gave an overestimation for 83% of the migration values generated in this study. The highest overestimation was 3.7 times the measured value. For all measurements, the predicted migration from the Migratest Lite program was greater than 50% of the observed value. The FDA model was found more accurately to predict migration in most situations but underestimated migration more frequently. Differences in the polymer specification had little effect on specific migration of the additives investigated.     

改性方式对红花籽粕可溶性膳食纤维理化性质和吸附特性的影响

为改善红花籽粕可溶性膳食纤维的部分理化性质和其吸附特性,以红花籽粕为原料,分别考察碱-酶法、酶-高温蒸煮法、碱-高温蒸煮法3种不同改性方式对其可溶性膳食纤维（SDF）的持水力、膨胀力、持油力等部分理化性质及对葡萄糖、阳离子、胆固醇和亚硝酸根离子吸附能力的影响。结果表明,碱-高温蒸煮法优于其他两种方法,碱-高温蒸煮法改性的红花籽粕SDF的持水力、膨胀力和持油力最佳,分别为5.58 g/g、3.98 mL/g和4.38 g/g;对葡萄糖吸附能力为16.08 mmol/g,在1% NaOH添加量为1～4 mL时,阳离子吸附效果最佳;在pH为2和7时,对胆固醇吸附能力分别为7.68 mg/g、10.14 mg/g,对亚硝酸盐吸附能力为56.43 μg/g、30.53 μg/g。     

Detection of olive oil adulteration with some plant oils by GLC analysis of sterols using polar column

A new method was developed to determine the presence of some refined vegetable oils in olive oil based on the sum of campesterol and stigmasterol percentages. Model systems of corn, soybean, sunflower and cotton seed oils in olive oil at levels of 5%, 10% and 20% were prepared. The unsaponifiables of these model systems were analysed by GLC using polar column with high thermal stability. An olive oil authenticity factor based on the summation of campesterol and stigmasterol percentages was established as an indicator of olive oil adulteration with vegetable oils. The results indicate the possibility to detect the presence as little as 5% of these plant oils in olive oil.     

固相微萃取-气质联用技术测定5种食用植物油挥发性成分

目的采用气相色谱-质谱(GC-MS)对大豆油、芝麻油、花生油、橄榄油、葡萄籽油5种食用植物油中挥发性成分进行分析。方法采用顶空固相微萃取(HS-SPME)技术对5种食用植物油中的挥发性成分进行萃取,并结合气相色谱-质谱(GC-MS)技术对挥发性成分进行测定。结果 5种食用植物油中共检测出101种挥发性化合物,其中大豆油11种、花生油28种、芝麻油65种、橄榄油25种、葡萄籽油5种。主要包括醛类、酯类、醇类、杂环类、酚类、酸类等10类物质。大豆油中主要的挥发性成分有戊醛、已醛和己酸,花生油中主要的挥发性成分有己醛、2,5-二甲基吡嗪和2,3-二氢苯并呋喃;芝麻油中主要的挥发性成分为5-甲基呋喃醛、2-吡咯甲醛、糠醇、愈创木酚、2-甲基吡嗪、2-乙基-6甲基吡嗪等;橄榄油中主要的挥发性成分为叶醇和4-己烯-1-醇乙酸酯;葡萄籽油中主要的挥发性成分为已醛。结论 5种食用植物油的挥发性物质的种类和含量上有很大区别,可为食用植物油的掺假鉴别提供参考依据。     

Partial substitution of pork backfat with extra-virgin olive oil in 'salami' products: effects on chemical, physical and sensorial quality

The effects on chemical, physical and sensory quality of the partial substitution of pork backfat with extra-virgin olive oil were studied in 'salami' products. Four 'salami' formulations, with 15% total fat, were prepared, in which 0, 33.5, 50 and 66.5% of pork backfat was substituted with extra-virgin olive oil. The partial pork backfat substitution with extra-virgin olive oil did not substantially affect the chemical, physical and sensorial characteristics of products, with the exception of water activity and texture. With regard to both oxidation and loss of organoleptic quality, the addition of extra-virgin olive oil, rich in mono-unsaturated fatty acids, did not decrease the shelf-life. The difference between samples with and without extra-virgin olive oil was a piquant note detected in the oil-added 'salami'. The formulation with 5% olive oil, corresponding to 33.3% substitution of pork backfat with olive oil, was judged best of all formulations. The results show that it is possible to produce this type of product, of good taste, similar to the traditional one, but with healthier features.     

云南11种油料作物油脂主要功能性成分评价

采用索氏抽提仪、气-质联用仪、高效液相色谱仪、紫外分光光度计对云南11种油料作物油脂中植物甾醇、角鲨烯、维生素E、类胡萝卜素和总酚含量进行测定分析。结果表明:植物油脂中的植物甾醇均以β-谷甾醇为主,β-谷甾醇含量最高的为菜籽油,总植物甾醇含量最高的也为菜籽油;橄榄油中角鲨烯的含量最高,达0.637%,明显优于其他植物油脂;红花籽油中维生素E含量最高,达19.90 mg/100 g(以α-生育酚计);花生油中类胡萝卜素含量最高,达18.10 mg/100 g;菜籽油中总酚含量最高,达247.91 mg/kg。通过主成分分析并对11种植物油脂的主要功能性成分综合得分进行排序,得分由高到低为菜籽油>橡胶籽油>花生油>红花籽油>橄榄油>大豆油>青刺果油>油茶籽油>油藤果油>核桃油>澳洲坚果油。因此,如果仅从脂溶性成分来看,菜籽油最优,橡胶籽油次之。