Consumer Sensory Evaluation and Flavor Analyses of Pasteurized and Irradiated Apple Cider with Potassium Sorbate

ABSTRACT: Consumer preference and acceptance sensory tests and volatile flavor analyses of apple cider (irradiated and pasteurized with potassium sorbate) were conducted in 2001 (599 panelists) and 2002 (577 panelists). In 2001, irradiated cider was preferred at 2 locations, whereas at the other 2 locations, neither sample was preferred. In 2002, the acceptability rating was 6.24 for irradiated cider and 6.41 for pasteurized cider, rating on a 7-point hedonic scale (1 = dislike very much; 7 = like very much). Acceptability of the pasteurized cider was significantly higher at 1 location. In both years, ciders with higher levels of esters and other compounds typical of apple flavor had higher preference and acceptability ratings.     

沸石负载壳聚糖对高酸苹果发酵酒澄清工艺

以鲁加6 号苹果发酵酒为原料,根据Box-Behnkend 的中心组合试验设计原理,在单因素的基础上采用响应面分析法,建立沸石负载壳聚糖澄清苹果酒的二次多项数学模型,并以苹果酒澄清度为响应值和等高线建立响应面,研究沸石负载壳聚糖添加量、处理时间、处理温度对苹果酒澄清效果的影响。结果表明：沸石负载壳聚糖澄清苹果酒的最佳工艺条件为沸石- 壳聚糖澄清剂添加剂量11.6g/L、处理时间47.6min、处理温度27℃;与常规法澄清苹果酒相比,经过处理的苹果酒澄清度提高了16.8%,可溶性蛋白含量、总酚含量均有显著降低,而总酸、可溶性固形物含量、儿茶素、绿原酸、咖啡酸含量变化不明显,表儿茶素含量降低。     

Statistical Modeling of D- and z-value of E. coli O157:H7 and pH in Apple Cider Containing Preservatives

ABSTRACT: The objective of this study was to model the heat resistance of E. coli O157:H7 in apple cider as a function of added sorbate, benzoate, and malic acid. Inactivation experiments were done at 47, 50, and 53 °C, and D and z values were calculated. Models for D₄₇, D₅₀, and D₅₃ showed that all 3 additives significantly decreased heat resistance. Furthermore, z-values increased with addition of preservatives and low pH. Model predictions showed that at 50 °C, 5-log reduction is attainable in a few minutes when the cider contains additives, while preliminary test results showed that at 20 °C, a 5-log reduction could be obtained in about 90 min in cider with 0.1% sorbate, 0.1% benzoate, and 1% malic acid.     

Changes in Apple Juice Flavor Compounds During Processing

Apple juice flavor fractions were collected at several stages during a commercial process. Replicated experiments were designed to collect samples from untreated pulp, from enzyme treated pulp, after pectinase treatment, after microfiltration (MF), and after pasteurization. Additional juice heating experiments were carried out. Six apple juice flavor compounds were identified based on to retention times and reported studies. The flavor profile changed at the different stages of the production line. Temperatures used (～57.2°C) for enzyme activation and MF tended to increase flavor compounds in apple juice except iso-butyl acetate. The higher temperatures used (～85°C) for pasteurization decreased all flavor compounds except propyl butyrate which increased. Results indicate apple juice may contain heat activated precursors of identified flavor compounds.     

Influence of Storage Time and Temperature on Absorption of Flavor Compounds from Solutions by Plastic Packaging Materials

ABSTRACT: Linear low-density polyethylene (LLDPE), oriented polypropylene (OPP), polycarbonate (PC), polyethylene terephthalate (PET film and PET bottle), and polyethylene naphthalate (PEN) were stored in a model solution containing 10 flavor compounds at 4, 20, and 40 °C and flavor absorption by the plastic materials was followed in time. The absorption rate and/or total amount absorbed increased considerably with temperature from 4 to 40 °C. Depending on storage temperature, total flavor absorption by the polyolefins (LLDPE and OPP) was 3 to 2400 times higher than by the polyesters (PC, PET, and PEN). Therefore, in the factor of flavor absorption, polyesters are preferred over polyolefins as packaging material.     

苹果酒原料及酵母对酿造的影响

以红富士苹果和浓缩果汁为原料酿造苹果酒。加入亚硫酸(120mg／L)于苹果汁中，24h后90％以上的游离SO2变为结合态，此后波动不大。研究显示，1．5‰的皂土澄清效果最好；鲜汁的产酒率明显高于浓缩汁，酒液中可溶性固形物和还原糖少。果酒酵母1#的产酒率最高，残糖最少，挥发酸最少，而且滴定酸、pH的变化幅度较少。与浓缩果汁相比，鲜果汁酿造的酒中含有的香气成分如活性戊醇 异戊醇、正戊醇、正己醇、苯乙酸乙酯较多。     

苹果酒香气成分代谢研究进展

苹果酒是指由苹果或苹果汁生产的一种低酒精度的发酵果酒,具有较高的营养成分和保健价值,备受人们的关注和喜爱。香气成分是评价苹果酒质量的关键因素。本文对苹果酒中主要香气成分的种类和来源、香气成分的分析方法、主要香气物质的合成途径等方面进行了综述,并对苹果酒香气成分代谢研究进行了展望。     

Inactivation of Escherichia coli with Power Ultrasound in Apple Cider

The use of acoustic energy to secure apple cider safety was explored. Inactivation tests were performed with Escherichia coli K12 at 40 °C, 45 °C, 50 °C, 55 °C, and 60 °C with and without ultrasound, followed by a validation test with E. coli O157:H7 at 60 °C. The cell morphology was observed with environmental scanning electron microscopy for samples treated at 40 °C and 60 °C. Physical quality attributes of the apple cider (pH, titratable acidity, °Brix, turbidity, and color) were compared for treated samples. The inactivation tests showed that sonication increased E. coli K12 cell destruction by 5.3‐log, 5.0‐log, and 0.1‐log cycles at 40 °C, 50 °C, and 60 °C, respectively. The additional destruction due to sonication was more pronounced at sublethal temperatures. At the lethal temperature of 60 °C, the rate of death by ultrasound was not significantly different compared with the thermal‐alone treatment. The inactivation of E. coli K12 with heat was described by 1st‐order kinetics, especially at 50 °C and 60 °C. For ultrasound treatments, concave upward survival curves were observed, which had a shape factor in the range of 0.547 to 0.720 for a Weibull distribution model. Extensive damage for ultrasound treated E. coli K12 cells, including cell perforation, was observed. Perforation is a unique phenomenon found on ultrasound‐treated cells that could be caused by liquid jets generated by cavitation. Titratable acidity, pH, and °Brix of the cider were not affected by ultrasound treatment. Minor changes in color and turbidity for ultrasound treated samples, especially for sonication at 40 °C for 17.7 min, were observed.     

果汁添加量对果汁酸奶风味的影响

以鲜牛乳、苹果汁为主要原料,以混合乳酸菌为发酵剂,采用单因素和正交试验,以产品风味和沉淀率为指标,对果汁酸奶的果汁添加量及稳定性进行研究。结果表明:①在发酵后将果汁和稳定剂加入到搅拌后的酸奶中,所得产品质地均匀,口感细腻,无分层,无乳清析出;②酸奶中添加0．10％的 PGA,0．25％的耐酸CMC和高达35％的苹果汁,可获得酸奶香味与苹果香味协调又能稳定贮存的活性苹果汁酸奶,该果汁酸奶可稳定贮存18天。     

不同包装方式对鲜切秦冠苹果贮藏品质的影响

以市售秦冠苹果为试材,结合柠檬酸保鲜剂处理,研究4 ℃贮藏条件下,普通包装、真空包装、高氧包装及充氮包装对鲜切秦冠苹贮藏品质变化规律的影响,确定最佳包装方式。结果表明:在综合鲜切苹果贮藏期各项指标的前提下,真空包装对鲜切苹果保鲜效果最佳,使鲜切苹果外观品质得以保持,延缓鲜切苹果的褐变进程和可溶性固形物含量降低速率,同时抑制了鲜切苹果贮藏期间多酚氧化酶(polyphenol oxidase,PPO)和过氧化物酶(peroxidase,POD)活性,减缓丙二醛(malondiadehyde,MDA)含量的升高。     

冷破碎红富士苹果浆发酵低度苹果酒工艺优化

以冷破碎红富士苹果浆为原料发酵制备低度苹果酒,通过分析不同酵母发酵周期的糖度、酒精度、pH和总酸筛选酵母菌株;在此基础上采用单因素与响应面试验以优化发酵工艺,确定冷破碎苹果浆发酵酒的最佳条件,通过分析酒品指标,与苹果清汁发酵酒的品质进行对比。结果表明,冷破碎苹果浆发酵酒的最佳工艺参数为：SY酵母发酵的初始糖度18%、酵母接种量0.1 g/L、发酵温度20℃;苹果浆发酵酒的残糖（7.5±0.46 g/L）、酒精度（7.8±0.1%）分别与苹果清汁发酵酒的残糖（7.3±0.31 g/L）、酒精度（8.0%±0.1%）差异不显著;苹果浆发酵酒的总酚（74.99±1.23 mg/100 mL）和有机酸（5.33±0.01 g/L）等成分含量高于苹果汁发酵酒（总酚47.5±2.2 mg/100 mL,有机酸5.01±0.03 g/L）。该结果可供苹果酒实际生产借鉴,也为苹果加工产业多元化发展提供思路。     

Microbial Populations and Malolactic Fermentation of Apple Cider using Traditional and Modified Methods

The evolution of yeasts and lactic acid bacteria was examined during two methods of cider making: the traditional employed unwashed apples of different varieties and the modified used a sole washed acidic apple variety with temperature control during the cider making process. The alcoholic fermentation was carried out mainly by Kloeckera apiculata and Sacharomyces cerevisiae species, and their distributions were similar in the two methods. In the traditional, the malolactic fermentation proceeded at the same time as alcoholic fermentation and the “piqure lactique” occurred. In the modified method, no malolactic fermentation took place. In all musts, a fundamentally heterofermentative lactic flora was found, with Lactobacillus species most abundant in the traditional process.     

Volatiles Production and Lipid Oxidation in Irradiated Cooked Sausage as Related to Packaging and Storage

Irradiation dose affected production of volatiles in vacuum-and aerobic-packaged cooked pork sausage, but its effect on TBARS was minor. Storage increased production of volatiles and changed their composition only in aerobic-packaged sausage. Among volatile components, 1-heptene and 1-nonene were influenced most by irradiation dose, and aldehydes by packaging type. TBARS and volatiles of vacuum-packaged irradiated cooked sausage did not correlate well. However, TBARS had very high correlation with amount of aldehydes, total volatiles, ketones and alcohols with long retention times in aerobic-packaged pork sausage. Heptene and 1-nonene could be indicators for irradiation; and propanal, pentanal, and hexanal for oxygen-dependent changes of cooked meat.     

Irradiated Ground Beef: Sensory And Quality Changes During Storage Under Various Packaging Conditions

Ground beef patties (irradiated with 2 kGy and nonirradiated) were packaged using oxygen permeable (polyolefin) or oxygen impermeable material (polyethylene). Samples were irradiated in air and stored in air; irradiated under vacuum and stored under vacuum; or irradiated under vacuum and stored in air. Changes in flavor, texture, juiciness or aftertaste were evaluated after either 1 or 7 days storage at 25°C prior to cooking. Irradiated "Vac/Air" samples were more tender, irradiated "Vac" samples were more moist, and irradiated "Air" samples had the least aftertaste. A 3 log₁₀ reduction in total aerobic counts was detected immediately after irradiation. No difference in lipid oxidation was found within the first week of storage, regardless of packaging atmosphere. Shelf life of ground beef patties was extended 55 days at 4°C.     

辐照技术对食品及包装材料迁移规律的影响

随着食品辐照技术的迅速发展,辐照食品的安全性也逐渐受到广大消费者的重视。辐照技术可以杀死食物中的致病微生物及部分的腐败细菌,抑制食物劣变的生理和生化过程,使食物不易腐败,起到保持食物新鲜的作用。辐照技术的优势很多,但是辐照技术对包装材料的物理化学变化也不容忽视,食品包装中大多数的食品是与包装材料直接接触,辐照对包装材料的影响也会直接影响到食品的安全。目前国内外对60Co-γ辐照技术和电子束辐照技术的应用最为广泛,文章将分别论述2种辐照技术的特点及研究、应用现状,旨在为今后辐照技术的安全发展提供参考。     

Dynamic Head Space Analyses of Orange Juice Flavor Compounds and Their Absorption into Packaging Materials

ABSTRACT: A simple, rapid, sensitive, and reproducible dynamic headspace gas chromatography (DH-GC) was developed to study the absorption of d-limonene, α-pinene, ethyl butyrate, and octanal into laminated polymeric packaging materials containing low-density polyethylene, polyethylene terephthalate, polyvinylidene chloride, and ethyl-ene-vinyl alcohol copolymers. The linear regression lines showed that the flavor compound peak areas were directly proportional to the concentrations of the standard flavor compounds with R ²≥ 0.97. The coefficients of variation for the DH-GC analyses were less than 4%. A test cell was designed to study orange juice flavor absorption into the packaging materials for 28 d at 25 °C. Ethyl butyrate or octanal absorption was not different among the 4 packaging materials ( P > 0.05). Addition of a polyethylene terephthalate and a ethylene-vinyl alcohol copolymer layer to the packaging materials reduced the d-limonene and α-pinene absorption by 20% and 50%, respectively.     

Characterization of Apples and Apple Cider Produced by a Guelph Area Orchard

Thermal stability of food-borne pathogens in apple cider is influenced by the composition of the product. As a preliminary step to determining the effect of pasteurization of apple cider on survival of E. coli O157:H7, a study was carried out to characterize apples and unpasteurized apple cider produced by a guelph area orchard. Samples of commercial unpasteurized cider and the constituent apples were collected over 13 wk from August to November 1998, and unpasteurized laboratory cider was made from the individual apple varieties. pH, titratable acidity (TA), turbidity, total microbial counts, total solids and °brix for filtered and unfiltered samples were measured. The maximum, minimum, and average values for all unpasteurized commercial cider samples were found to be: pH, 3.71, 3.17, and 3.43; TA, 93.47, 49.46, and 69.95 mL of 0.1 N NaOH/100 mL; total solids, 13.21, 10.93, and 11.90%; °brix, 13.01, 11.17, and 12.02; turbidity, 238.1, 145.1, and 204.9 NTU; and total plate count, 4.91, 2.61, 3.75 log cfu·mL⁻¹. There were no significnat differences (P>0.05) between filtered and unfiltered samples. In addition, in commercial unpasteurized cider, there were no significant differences (P>0.05) with respect to any of the factors with time of processing. The composition of the unpasteurized laboratory cider made form individual apple varieties was dependent on the variety, but was generally within the ranges from published literature values. Mclntosh apples showed a significant (P≤0.05) decrease in TA with time of harvest. The results suggest that it is necessary to take the composition of commercial apple cider into account when developing thermal inactivation models for food-borne pathogens.     

Antimicrobial Activity and Synergistic Effect of Cinnamon with Sodium Benzoate or Potassium Sorbate in Controlling Escherichia coli O157:H7 in Apple Juice

ABSTRACT: Antimicrobial effects of cinnamon, sodium benzoate, potassium sorbate, and combinations were examined against Escherichia coli O157:H7 in apple juice at 8°C and 25°C. E. coli O157:H7 was reduced by 1.6 log colony-forming units (CFU)/mL at 8°C and 2.0 log CFU/mL at 25°C by 0.3% cinnamon. At 8°C, 5.2 log CFU/mL of E. coli O157:H7 was eliminated in 11 d by 0.3% cinnamon with 0.1% sodium benzoate, and in 14 d by 0.3% cinnamon with 0.1% potassium sorbate. At 25°C, 5.3 log CFU/mL E. coli O157:H7 was eliminated in 3 d by the same combinations. A synergistic effect was observed between cinnamon and preservatives against E. coli O157:H7 at 8°C and 25°C.