高静压处理对黄桃罐头微生物和质构的影响

以黄桃罐头为试材,研究了高静压处理的杀菌效果,并用质地多面分析(TPA)方法,对高静压造成黄桃质构的变化进行分析。结果表明,400MPa下处理25min即可杀灭所有细菌,300MPa下处理15min就能杀灭所有霉菌和酵母菌。高静压处理(600MPa,5min)后黄桃罐头的硬度、凝聚性和咀嚼性与未处理无显著差异,但显著好于热处理。高静压技术能使黄桃罐头达到商业无菌,并保持良好质构。      

高静压下添加酪朊酸钠鸡肉肠制品保水性与质构特性的相关性研究

在50～600MPa高静压和5～40min保压时间范围内单因素考察添加1.5%酪朊酸钠鸡肉肠制品保水性与质构特性的相互影响规律,并用电镜从微观结构上分析其机理。结果表明:与未受压的对照样比较,200～500MPa高静压和10～30min保压时间都能显著增强其保水特性(P<0.01),过低压力50MPa和过高压力600MPa有明显降低保水性现象(P<0.01);制品质构特性(硬度、咀嚼性)随着压力增大而先迅速后平缓增大;而保压时间对鸡肉肠制品的保水性、质构特性的影响不显著。与保压时间比较,不同压力水平处理下的制品保水性与质构特性有着更加显著的相关性(P<0.01),提高保水性同时能明显改善其质构特性。     

高静压处理对预制绿芦笋品质的影响

绿芦笋嫩茎含水量高,呼吸作用较强,采收后不耐贮藏。高静压技术(High hydrostatic pressure,HHP)是一种新兴的最少加工技术,为解决绿芦笋采后损失问题提供了有效途径。本文研究了高静压处理对预制绿芦笋(Asparagus officinalis L)杀菌效果与品质的影响。分别在300、400、500、600 MPa压力和室温(25℃)下,研究了HHP处理绿芦笋1、3、5、10、15、20 min对微生物的杀灭效果。在保证杀菌效果的基础上,筛选出3组HHP处理参数,研究了高静压处理后预制绿芦笋贮藏品质的变化。结果表明:随着压力升高及保压时间延长,HHP的杀菌效果逐渐增强;霉菌和酵母对压力比较敏感,300 MPa处理3 min就能全部杀灭;300 MPa处理15 min、400 MPa处理10 min、500 MPa处理5 min、600 MPa处理3 min后,绿芦笋菌落总数含量均低于100 cfu/g。Weibull模型在压力300~600 MPa范围内拟合度较高(相关系数R~2>0.970)。贮藏期间,与传统热处理相比,3组高静压处理较好的保留了绿芦笋的色泽、质构、维生素含量等品质。综上所述,500 MPa处理5 min的预制绿芦笋贮藏期可达21 d,品质优于其它两组高静压处理。      

高静压对桃汁杀菌、钝化酶活性的效果

研究在不同处理压力和时间条件下,高静压加工技术对桃汁中微生物(细菌总数、霉菌、酵母菌、大肠菌群)以及酶(多酚氧化酶、果胶甲基酯酶、脂肪氧化酶)的影响。结果表明:经400MPa、5min高静压处理即可完全杀灭桃汁中的微生物;在400MPa和500MPa条件下,桃汁中的多酚氧化酶和脂肪氧化酶的活性出现了不同程度的激活现象,但在600MPa时,随着处理时间的延长,其活性逐渐降低,经30min处理后,分别被钝化了0.7662和0.641。而果胶甲基酯酶在400、500、600MPa条件下,出现了不规律的激活或钝化现象。另外,研究表明在高静压加工前增加漂烫工艺,可以有效杀灭桃汁中的微生物及钝化酶活性。     

高静压对添加酪朊酸钠鸡肉糜制品特性及其微观结构的影响

在肉制品加工中运用高静压技术对其改性将得到发展。研究侧重在50～600MPa和5～40min范围内单因素考察添加1.5%酪朊酸钠鸡肉糜制品保水性、质构、凝胶强度、色泽特性的影响,并从微观结构上分析其作用机理。结果表明:与未受压的对照样比较,200～500MPa和10～30min都能显著增强其保水特性(p<0.01),过低压力50MPa和过高压力600MPa有明显降低保水性现象(p<0.01);制品质构特性(硬度、咀嚼性)随着压力增大而增大;凝胶强度也同样随着压力增加而增加,但在600MPa出现明显劣化(p<0.01),从侧面反映了保水性变化特点;制品色泽(白度、彩度)基本上随着压力增大和时间延续均分别逐渐增大和下降;而保压时间对鸡肉糜制品的保水性、质构与凝胶强度的影响相对有限。综合分析,300MPa、20min的高静压条件处理可获得较高出品率、较好质构特性和色泽的添加酪朊酸钠鸡肉糜制品。     

高静压对鸡肉凝胶品质影响的试验研究

通过单因素试验,在压力100~400 MPa、保压时间15 min、室温条件下,考察高静压对低盐(食盐添加量1%)鸡肉凝胶色泽、pH值、持水性与质构品质的影响。研究结果表明:200 MPa以上的高静压可导致鸡肉凝胶亮度的显著下降、以及凝胶硬度、弹性和咀嚼性的显著增加;300 MPa以上的高静压可引起鸡肉凝胶pH值和黏结性的显著升高(P<0.05);100 MPa与300 MPa压力使鸡肉凝胶的蒸煮损失率CL低于对照组,而200 MPa压力导致CL升高(P<0.05);100~400 MPa的高静压对鸡肉凝胶的保水性无显著影响(P>0.05)。因此,300 MPa的高静压可形成高硬度、高弹性与高黏结性、低CL值的低盐鸡肉糜凝胶制品。     

高静压对黄桃质构相关组分模拟体系的影响

以黄桃质构相关组分(细胞壁物质)为模拟体系,探究了高静压处理、热处理以及贮藏过程对细胞壁物质持水性及其果胶各组分和纤维素含量变化的影响。结果表明:与热处理相比,高静压处理对细胞壁物质的持水性、果胶各组分含量和纤维素含量均无显著影响。与常温贮藏相比,低温贮藏对高静压处理及热处理的细胞壁物质的持水性、各果胶组分含量和纤维素含量无显著影响。相关性分析显示:碱溶性果胶与水溶性果胶之间,碱溶性果胶、水溶性果胶与持水性之间相关性较高。     

气体结合高静压对预制莴笋货架期品质的影响

为了方便莴笋在人们日常生活中的摄入,满足人们对预制产品营养与品质的需求,采用高静压(High Hydrostatic Pressure,HHP,500 MPa,5 min)分别结合二氧化碳、氮气,以及抽真空体系处理新鲜莴笋,研究莴笋贮藏期间叶绿素含量、色泽、质构和微生物的变化。新鲜莴笋切丝烫漂30 s后称量包装热封,气体结合高静压处理后于4℃冷库中贮藏。结果表明:二氧化碳结合高静压处理后的鲜切莴笋货架期长达35 d,且叶绿素含量,色差CIE-L*a*b*值,质构,均优于氮气结合高静压组和真空结合高静压组,菌落总数低于其他两组。二氧化碳结合高静压能提高预制莴笋的贮藏品质并有效延长预制莴笋的货架期。     

高静压技术生产方便湿面条的工艺研究

利用高静压技术对生鲜面条进行二次加工,生产方便湿面条。首先通过单因素实验,分别改变保压压力(100~500 MPa)、保压时间(1~13 min)、保压温度(20~30℃)三个高静压处理条件,以最佳煮制时间为考核指标,确定正交实验条件。之后通过正交实验综合研究了最佳煮制时间、糊化度、菌落总数、质构性质的变化,结合感官评价确定最佳高静压处理条件为压力400 MPa,时间10 min,温度20℃。此条件下,最佳煮制时间缩短为185 s,保质期可达两周以上。      

高静压加工对新鲜蛋液微生物及品质的影响

研究在不同处理压力和时间条件下,高静压对新鲜全蛋液微生物(细菌总数、大肠菌群)、色泽、乳化特性(乳化活力、乳化稳定指数)及起泡特性(起泡性、泡沫稳定性)的影响。结果表明:200 MPa处理10 min,全蛋液微生物指标已符合国家标准;相比空白组,400 MPa处理10 min,全蛋液乳化活力及乳化稳定性显著增加,300 MPa处理20 min及400 MPa处理10 min全蛋液起泡性较好,而400 MPa处理10~15 min及500 MPa处理5~15 min可使全蛋液颜色更鲜亮。综上,适当的高静压处理可使全蛋液达到有效杀菌且改善其品质的目的。     

超高压处理对养殖大黄鱼保鲜效果的影响

研究超高压处理对养殖大黄鱼保鲜效果的影响,经不同超高压（100、200、300、400、500 MPa,保压时间10、15 min）处理后,研究其pH值、aw、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、硫代巴比妥酸（thiobarbituric acid,TBA）值、三甲胺（trimethylamine,TMA）值、菌落总数的变化。其次,研究大黄鱼在4 ℃冷藏期间pH值、aw、TVB-N值、TBA值、TMA值、菌落总数的变化情况。结果表明,超高压处理后大黄鱼的pH值随着压力的升高而增加;aw随压力的升高而减小;TVB-N值随着压力的增加呈减小的趋势;TBA值随着压力的上升而增大;TMA值略有上升但幅度不大;菌落总数随压力增加明显降低。实验组的大黄鱼pH值和aw在4 ℃贮藏期先升后降;500 MPa、15 min 处理后45 d,大黄鱼的TVB-N值和TMA值增加,含量分别不超过35 mg/100 g和5 mg/100 g,TVB-N值和TMA值得到了有效控制;第45天500 MPa、15 min处理组大黄鱼的菌落总数为5.7×104 CFU/mL。因此,压强500 MPa保压时间15 min为养殖大黄鱼最适合的保鲜条件。     

温湿地域黄桃的制罐适宜性研究

本实验通过对黄桃果实进行解剖,采用目测、嗅闻、品尝的方法,运用质构和色差仪进行系统分析,研究温湿地域黄桃鲜果和罐头的感官品质特征、鲜果的物理性状、果肉色泽特性以及果肉质构特性,建立黄桃鲜果与罐头的感官品质5级综合评价标准体系、19个评价指标,将研究结果与市场相结合确定了7个关键技术指标,并对温湿地域的5个黄桃鲜果和罐头进行了客观评价分析。研究发现果肉质构的硬度、弹性以及黏力与罐头的品质呈正相关;果肉质构方面,罐头较鲜果下降率,弹性黏力硬度。总色差DE*值与果肉色呈正相关;当鲜果总色差DE*值接近50,罐头DE*值鲜果DE*值,且变化率超过10%时,果肉色泽艳丽呈深橙黄。筛选出优质制罐品种4号(金露),其感官品质综合评价、完整性(条桃)、肉色、香气、质地和风味的标准分析平均值分别为1.63、1.13、0.88、0.75、0.75、1.50;平均单果质量183.16 g、纵径和横径分别为7.04 cm和7.10 cm、果肉厚度2.24 cm、可食率81.48%、果核率6.31%、质构硬度16.6 g、弹性0.42 mm、黏力2.0 g、总色差DE*值56.39。     

Optimization of high hydrostatic pressure processing for the preservation of minimally processed peach pieces

Consumers demand fresh-cut fruits, free from additives and with fresh appearance. However, the alteration caused by the tissue processing limits their shelf life. The aim of this work was to optimize the pressure level (from 400 to 600 MPa) and the holding time (from 1 to 9 min) of the high pressure processing (HPP) to achieve enzyme inactivation while preserving texture and color of minimally processed peaches. Peach cylinders were processed by combining dipping in organic acid solution, with vacuum packaging and HPP at room temperature. Results showed that higher pressure levels were more effective to inactivate enzymes and to preserve color than longer times. In addition, long treatments affected the microstructure and the texture of the tissues more seriously. Finally, a desirability study and a principal component analysis were performed. These showed that the optimal treatment would be 585 MPa and 1 min and that the best treatment of the ones studied was 600 MPa for 5 min.Industrial RelevanceThere is an increasing demand for minimally processed fruits as a result of their convenience and fresh-like characteristics. Although consumers are familiar with the consumption of canned peaches, the nutritional profile of this product is far from being optimal, and therefore minimal processing offers the unique advantage of maintaining the original quality of the fresh fruit. However, this product is prone to suffer alterations such as browning and softening. High pressure processing (HPP) is proposed as a non-thermal technology able to suitably preserve minimally processed peaches. This study aimed to optimize the conditions of the HPP treatment, to achieve enzyme inactivation while maintaining texture and color. The promising results obtained can help promote the use of HPP as an alternative to preserve the quality and extend the shelf life of minimally processed fruits.     

Evaluation of Consumer Acceptance and Quality of Thermally and High Hydrostatic Pressure Processed Blueberries and Cherries Subjected to Cellulose Nanofiber (CNF) Incorporated Water-Resistant Coating Treatment

This study evaluated the influence of cellulose nanofiber (CNF) incorporated layer-by-layer water-resistant coating on consumer acceptance of blueberries and cherries processed in light syrup thermally (TP, 97 °C for 7 min) or non-thermally (high hydrostatic pressure (HHP), 414 MPa for 10 min). The coating technique was validated on canned blueberries in a commercial canning operation. Consumers (n?=?75 and 77 for blueberry and cherry study, respectively) scored overall, color, aroma, and texture likeness of coated and uncoated processed fruits using a 9-point hedonic scale and firmness intensity using a 5-point just about right (JAR) scale. Coating treatment significantly (P?<?0.05) increased aroma and texture liking scores of TP and HHP blueberries compared with uncoated ones, but did not impact overall and color liking scores. Coated TP (2.67) and HHP (2.96) blueberries received closer to JAR score in firmness that uncoated ones (1.88 and 2.57, respectively). Informing consumers about the benefit of developed coatings altered consumers’ attitude from negative (~?80 and ~?57% gave “neutral” and “disliking” scores on TP and HHP samples, respectively) into positive status (“I would like the overall appearance”). Coating treatment resulted in higher aroma liking scores in HHP cherries, but decreased (P?<?0.05) overall and color liking scores on both TP and HHP cherries due to the presence of visible coating substances onto fruit surface. In commercial canning process, coated blueberries showed great retention of bioactive compounds and firmness. This study demonstrated that CNF incorporated layer-by-layer coating is promising to produce high quality of processed fruits in light syrup.     

Effect of innovative food processing technologies on microbiological quality,colour and texture of fresh-cut potato during storage

The objective of this work was to find the optimal conditions that extend the shelf life of fresh-cut potatoes using innovative food processing technologies. Potato cultivar, Longshu No. 10, was treated with high hydrostatic pressure (HHP) with 200 MPa (HHP 200) for 2, 6 and 10 min, and HHP with 400 MPa (HHP 400) for 1, 2 and 6 min; electrolysed water with pH 5.2 (EW 5.2) for 2, 5 and 10 min of soaking; and ultrasonic (US) with 200 W (US 200) for 5 and 10 min, and US with 500 W (US 500) for 5, 10 and 15 min. Microbiological quality, colour and textural changes and polyphenol oxidase (PPO) activity were determined during 12 days of storage at 4 °C. Processing technologies showed an effect on reducing the microbial load of fresh-cut potatoes with respect to control. EW (5 min) and US (500 W for 15 min) were the best treatments in terms of colour, and these treatments did not modify the texture of the fresh-cut potato, which make them promising for extending the shelf life of fresh-cut potatoes. Also, the US treatment showed the lowest PPO activity.     

Combined effect of high hydrostatic pressure treatment and hydrogen peroxide on Salmonella Enteritidis in liquid whole egg

The effects of high hydrostatic pressure treatment (HHP) of 250, 350, 450 MPa and hydrogen peroxide additions at different concentrations of 0.1, 0.5, 1% in liquid whole egg following high hydrostatic pressure treatment at 250 MPa at 20 °C on Salmonella Enteritidis PT4 in liquid whole egg were investigated. At 20 °C for 5 min treatment, 56.63 and 49.38% injury were determined for the treatment pressures of 250 and 350 MPa, respectively. Injury was not detected and total destruction of Salmonella Enteritidis PT4 was obtained for 5 min treatment at 450 MPa. The obtained results indicated that HHP was a more effective treatment than preheating for the enhancement of the effectiveness of H₂O₂. In order to minimize the adverse effect of HHP on food texture, the HHP treatment of 250 MPa was used throughout this study. Therefore, treating with 0.5% H₂O₂ following 5 min HHP at 250 MPa was determined as an effective way of Salmonella Enteritidis destruction in liquid whole egg. The catalase activity retention was determined as 62.26±0.6% after 3.5 min treatment of LWE at 60 °C. A 5-min treatment at 250 and 450 MPa at 20 °C of LWE resulted in a 78.67±2.1 and 65.01±1.8% retention of catalase activity, respectively.     

High hydrostatic pressure modification of whey protein concentrate for improved body and texture of lowfat ice cream

Previous research demonstrated that application of high hydrostatic pressure (HHP), particularly at 300 MPa for 15 min, can enhance foaming properties of whey protein concentrate (WPC). The purpose of this research was to determine the practical impact of HHP-treated WPC on the body and texture of lowfat ice cream. Washington State University (WSU)-WPC was produced by ultrafiltration of fresh separated whey received from the WSU creamery. Commercial whey protein concentrate 35 (WPC 35) powder was reconstituted to equivalent total solids as WSU-WPC (8.23%). Three batches of lowfat ice cream mix were produced to contain WSU-WPC without HHP, WSU-WPC with HHP (300 MPa for 15 min), and WPC 35 without HHP. All lowfat ice cream mixes contained 10% WSU-WPC or WPC 35. Overrun and foam stability of ice cream mixes were determined after whipping for 15 min. Ice creams were produced using standard ice cream ingredients and processing. The hardness of ice creams was determined with a TA-XT2 texture analyzer. Sensory evaluation by balanced reference duo-trio test was carried out using 52 vol.nteers. The ice cream mix containing HHP-treated WSU-WPC exhibited the greatest overrun and foam stability, confirming the effect of HHP on foaming properties of whey proteins in a complex system. Ice cream containing HHP-treated WSU-WPC exhibited significantly greater hardness than ice cream produced with untreated WSU-WPC or WPC 35. Panelists were able to distinguish between ice cream containing HHP-treated WSU-WPC and ice cream containing untreated WPC 35. Improvements of overrun and foam stability were observed when HHP-treated whey protein was used at a concentration as low as 10% (wt/wt) in ice cream mix. The impact of HHP on the functional properties of whey proteins was more pronounced than the impact on sensory properties.