基于感应离子电流的钙强化水果浸渍技术

快速浸渍开发营养强化食品,目前大多采用脉动真空处理。依靠交变磁通在浸渍液回路体系中产生钙离子电流,对4种孔隙率的水果进行钙离子强化处理。选取浸渍液浓度、处理时间和孔隙率为影响因素,通过单因素及响应面试验,考察浸渍技术对4种水果的钙强化效果,建立孔隙率在5.4%~17.8%范围的水果钙含量预测模型。结果表明:感应离子电压不随浓度改变,浓度越高,磁能转换为电能的效率就越高,钙离子浸渍量提高。组织孔隙率是钙渗入量的主要影响因素,产品钙含量分布不均。选取实测孔隙率为6.7%的桃作为钙含量预测模型验证对象,通过离子电流处理后发现模型能较好地预测果品渗入的钙含量。该技术针对强电解质离子溶液处理植物性原料,有潜力作为一种快速浸渍技术,实现功能性食品的开发。     

水杨酸处理对鲜切富士苹果抗氧化性的影响

主要探讨了外源水杨酸(SA)溶液处理对贮藏中的鲜切苹果在一段时期内的生理生化的影响。选用0.25mmol.L-1的水杨酸溶液处理鲜切苹果,清水浸泡为对照,5℃贮藏,并测定此条件下鲜切苹果生理生化的变化情况。实验结果表明,0.25mmol.L-1的水杨酸溶液处理可以有效地抑制鲜切苹果中谷胱甘肽还原酶(GR)和抗坏血酸过氧化物酶(APX)的活性,抑制鲜切苹果膜脂过氧化的程度和超氧阴离子O2-.的产生,减少过氧化氢(H2O2)的含量,并防止了总酚和VC含量的下降。由此可见,0.25mmol.L-1的水杨酸溶液处理可以提高鲜切苹果的抗氧化性以及保护其营养物质,改善鲜切苹果的内在品质。     

氯化钙对超高压处理的鲜切马铃薯硬度改善效果的研究

超高压（Ultra-high pressure,HPP）会造成鲜切马铃薯硬度的下降,为探究氯化钙对HPP处理的鲜切马铃薯硬度的改善效果,以鲜切马铃薯为原料,在不同氯化钙处理浓度、时间和浸泡方式下对HPP处理的鲜切马铃薯硬度的变化进行研究。结果表明：氯化钙真空浸渍硬度改善效果优于普通浸泡;在此基础上,采用响应面试验对氯化钙的改善效果进行优化分析得出不同浓度氯化钙及不同真空浸渍时间与不同超高压压力、压力作用时间作用于鲜切马铃薯是交互影响的,且氯化钙溶液浓度对鲜切马铃薯的质地影响最大。在HPP压力为300 MPa,作用时间10 min结合1.0%CaCl2,真空浸渍10 min 的处理条件下,鲜切马铃薯硬度值最大,为3284.83g,与未处理的鲜切马铃薯硬度相当,钙离子含量最高,为3157.82 ug/g,显著高于未处理组钙离子含量。     

真空浸渍对苹果强化营养的研究

本研究将红富士苹果在常温下(25℃)分别用乳酸钙(CL)的蔗糖混合溶液和葡萄糖酸锌(ZG)的蔗糖混合溶液置于80、100mbar真空度下浸渍15min,通过改变复压时间、蔗糖溶液浓度(°Brix)以及乳酸钙、葡萄糖酸锌添加量,对样品真空浸渍后的矿物含量和理化指标进行测定比较。结果表明,当复压时间分别选择为30min和25min、蔗糖浓度30°Brix、CL添加量5%、ZG添加量0.02%时,真空浸渍后的每200g样品中对应的钙、锌元素含量可分别达到每日参考摄入量(DRI)值的16.53%和37.67%,CL(乳酸钙)同时可以较好地保持样品在浸渍前后的抗压强度,ZG(葡萄糖酸锌)则有助于保持样品颜色稳定性。     

短波紫外线控制鲜切苹果褐变与其活性氧代谢的相关性

为研究短波紫外线（ultraviolet-C,UV-C）处理对鲜切苹果褐变控制与活性氧（reactive oxygen species,ROS）代谢的相关性,分析贮藏过程中UV-C处理后鲜切苹果的ROS水平、抗氧化相关酶活力、抗氧化物质（VC）含量以及非酶抗氧化能力的变化。结果表明：UV-C处理能够有效抑制鲜切苹果的褐变,降低超氧阴离子自由基产生速率和H2O2、丙二醛（malondialdehyde,MDA）含量;同时,UV-C处理能够有效提高抗氧化相关酶（超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化酶和谷胱甘肽还原酶）活力以及VC含量,减缓鲜切苹果非酶抗氧化能力（1,1-二苯基-2-三硝基苯肼自由基、2,2’-联氮-双(3-乙基苯并噻唑-6-磺酸)阳离子自由基清除能力和还原能力）在贮藏过程中的下降;相关性分析与主成分分析结果显示,鲜切苹果褐变程度与ROS水平和MDA含量呈显著正相关（P＜0.05）,与抗氧化酶活力和非酶抗氧化能力呈显著（P＜0.05）或极显著（P＜0.01）负相关,且UV-C处理组鲜切苹果的ROS代谢能力高于对照组。因此,推测UV-C处理可能通过调节鲜切苹果的ROS代谢进而控制其贮藏过程中的褐变。     

马齿苋提取物对鲜切苹果褐变的影响

酶促褐变是影响鲜切果蔬品质及商业价值的关键问题之一。为探究马齿苋提取物在果蔬保鲜方面的应用价值,以鲜切苹果为研究材料,采用质量分数0.05%马齿苋提取物溶液浸泡鲜切苹果5min,在(4±1)℃存放8d。以鲜切苹果的褐变指数、多酚氧化酶(polyphenol oxidase,PPO)活力、苯丙氨酸解氨酶(phenylalanine ammonia-lyase,PAL)活力、过氧化氢酶(catalase,CAT)活力、过氧化物酶(peroxidase,POD)活力、丙二醛(malondiadehyde,MDA)含量、抗坏血酸含量以及DPPH自由基清除能力为评价指标,分析马齿苋提取物对鲜切苹果褐变及贮藏品质的影响。结果表明:与蒸馏水对照组相比,马齿苋提取物溶液处理能有效抑制鲜切苹果的褐变程度,在降低POD、PPO和PAL活力方面也有明显效果,能够在保证膜完整性的基础上减少细胞膜出现的损伤。相关性分析表明:鲜切苹果的褐变指数与CAT活力、抗坏血酸含量、DPPH自由基清除能力呈现极显著负相关(P<0.01),与MDA含量、PPO活力、POD活力、总酚含量呈极显著正相关(P<0.01)。马齿苋提取物溶液处理的鲜切苹果抗褐变效果较好,同时贮藏后鲜切苹果的抗氧化能力也有一定提高。     

复合保鲜剂对鲜切苹果贮藏品质的影响

以鲜切苹果为试材,研究不同浓度柠檬酸、壳聚糖及D-异抗坏血酸钠(D-sodium erythorbate,D-SE)复合保鲜剂处理5 min,4℃贮藏期间鲜切苹果贮藏品质特性的变化规律。结果表明:复合保鲜剂处理组可保持鲜切苹果感官品质、抑制鲜切苹果多酚氧化酶(PPO)及过氧化物酶(POD)活性,对鲜切苹果有较好的保鲜效果;1.0%柠檬酸+0.5%壳聚糖+1.0%D-异抗坏血酸钠溶液处理组优于其他处理组,能在4℃贮藏12 d内保持鲜切苹果外观品质与食用品质品质,有效抑制鲜切苹果果肉褐变,延缓硬度和TSS含量降低速率,降低与褐变有关的多酚氧化酶(PPO)及过氧化物酶(POD)活性。     

半胱氨酸控制鲜切苹果褐变的生理机制

为研究半胱氨酸对鲜切苹果褐变控制的生理机制,以鲜切苹果为研究对象,采用0.5 g/L的半胱氨酸溶液处 理1 min,分析贮藏过程中鲜切苹果褐变指数（browning index,BI）、多酚氧化酶（polyphenol oxidase,PPO）和 抗氧化酶活力、抗氧化物质和丙二醛（malondialdehyde,MDA）质量摩尔浓度及抗氧化能力的变化。结果表明, 与蒸馏水处理相比,半胱氨酸处理能够显著抑制鲜切苹果的褐变,在贮藏初期半胱氨酸处理降低了鲜切苹果的PPO 活力,同时在贮藏过程中不同程度提高了鲜切苹果的抗氧化酶活力以及抗氧化能力,减缓了抗氧化物质在贮藏过程 中的损失,并且抑制了MDA的积累。相关性分析显示,鲜切苹果的BI值与抗坏血酸含量、过氧化氢酶活力以及抗 氧化能力呈极显著负相关（P＜0.01）,与MDA质量摩尔浓度呈极显著正相关（P＜0.01）。因此,半胱氨酸可能是 一方面通过抑制鲜切苹果的PPO活力,另一方面通过提高其抗氧化能力,延缓贮藏过程中的组织褐变。     

丝素-壳聚糖复合涂膜对鲜切苹果保鲜性能的研究

以鲜切苹果为研究材料,分别以0.6%丝素蛋白+1%壳聚糖溶液(b组)、0.6%丝素蛋白溶液(c组)、1%壳聚糖溶液(d组)进行保鲜处理,以未经处理的a组为对照,研究丝素蛋白-壳聚糖涂膜对鲜切苹果的保鲜效果。结果表明:在相同储藏期(8 day)和储藏环境下(4℃),与a组相比,三组处理的保鲜效果最好的为b组,其褐变度减少,失重率降低,维持维生素C的含量,丙二醛生成量减少,起到了较好的保鲜效果。根据试验结果分析认为,b组有效地保持了鲜切苹果在贮藏期间的品质。     

螺旋藻多糖对鲜切苹果的保鲜效果

以红富士苹果为材料,研究螺旋藻多糖对鲜切苹果酶促褐变中关键酶及相关生理生化指标的影响。结果表明,螺旋藻多糖可显著抑制PPO活性、增强SOD和POD活性,从而减缓鲜切苹果的褐变程度;螺旋藻多糖可使鲜切苹果中总蛋白质、蔗糖、抗坏血酸、谷胱甘肽含量维持在较高能量水平,为延长贮藏期提供物质基础;螺旋藻多糖还有助于鲜切苹果中总酚的保持,提升鲜切水果抗逆性物质浓度,整体表现出显著综合保鲜效果。试验为螺旋藻多糖在鲜切水果保鲜中的应用提供研究思路和理论基础。     

Effect of Tapioca Starch/Decolorized Hsian-tsao Leaf Gum-Based Active Coatings on the Qualities of Fresh-Cut Apples

The effect of tapioca starch/decolorized hsian-tsao leaf gum (dHG)-based edible coatings with various food additives (including ascorbic acid, calcium chloride, and cinnamon oil) on the qualities and shelf life of fresh-cut “Fuji” apple pieces was investigated during the refrigerated storage. The initial respiration rate, headspace gas composition, color, texture, microbial quality, peroxidase activity, and sensory qualities were analyzed. The results were also compared to those for samples submerged in distilled water and the samples treated with 120-ppm chlorine solution widely used in the industry. It was found that ascorbic acid and cinnamon oil delayed the browning of fresh-cut apples effectively when being applied in the starch/dHG-based edible coating solutions. In combination with calcium chloride, starch/dHG coated fresh-cut apples retained satisfactory firmness. Incorporation of cinnamon oil in starch/dHG coatings significantly reduced the growth of microorganisms, respiration rate, CO₂, and ethylene production of fresh-cut apples, but these apple pieces received lower scores in overall preference during sensory evaluation. Among the starch/dHG-based active coatings studied, starch/dHG coatings with ascorbic acid and calcium chloride are suggested for fresh-cut apples, as they could enhance qualities in terms of color and firmness, and prolong the shelf life up to 5–7 days by providing reasonable microbial quality.     

Nutritional, Sensory, and Physicochemical Properties of Vitamin E- and Mineral-fortified Fresh-cut Apples by Use of Vacuum Impregnation

ABSTRACT: This study evaluated fresh-cut apples (Fuji) fortified with vitamin E and minerals by use of the vacuum impregnation (VI) technique. A 20% diluted high fructose corn syrup (HFCS) or 1% calcium caseinate (CC) aqueous solution were used as VI solutions, and 0.4% a-tocopherol acetate, 7.5% Gluconal Cal° (GC), and 0.04% zinc lactate (ZL) were incorporated into the VI solutions for the purpose of nutritional fortification. For VI treatment, fresh-cut apples were immersed in VI solutions subjected to vacuum at 100 mm Hg for 15 min following atmospheric restoration for 30 min. Apples were packed in the polyvinyl chloride (PVC) hinged clear containers and stored at 2 °C and 88% RH up to 3 wk. Nutritional contents, consumer sensory acceptability, microbial population, color, and firmness of the apples were evaluated during cold storage. In 100 g of fresh-cut apples, vitamin E content increased more than 100 times, and calcium and zinc contents increased about 20 times compared with unfortified apples. Consumer sensory study demonstrated that HFCS-treated apples were highly accepted by consumers in respect to overall liking, color, and texture quality. Bacterial growth was concurrently detected in all apples, but the total plate accounts were under 2.6 log colony-forming units (CFU)/ g apple at the end of 7 d of storage, significantly lower than the industrial standard. Instrumental analysis indicated that VI treatment in both HFCS and CC solutions significantly decreased color change and retained the firmness of fresh-cut apples during 3 wk of cold storage.     

Quality of Fresh-cut Apple Slices as Affected by Low-dose Ionizing Radiation and Calcium Ascorbate Treatment

ABSTRACT: Although ionizing radiation effectively inactivates food-borne bacterial pathogens in fresh-cut fruits and vegetables, it may adversely affect product quality. In this study, the effects of calcium ascorbate (CaA) and ionizing radiation on quality of 'Gala' apple slices under modified atmosphere packaging were investigated. 'Gala' apple slices, treated with water or 7% CaA followed by either nonirradiation (0 kGy) or irradiation at 0.5 and 1.0 kGy, were stored at 10°C for up to 3 wk. The titratable acidity, pH, firmness, ascorbic acid content, color, and microflora population were measured weekly throughout storage. Irradiation did not affect titratable acidity and pH of sliced apples. Fruit slices softened during irradiation and storage, but this decrease in firmness during storage was reduced by the CaA treatment. Although the ascorbic acid content of apple slices treated with CaA decreased rapidly during storage, the ascorbic acid content was always higher in those treated samples than in the apple slices treated with water. Irradiation decreased both L * and hue values of apple slices. Hue values decreased during the entire storage period while L * increased during the 1st wk of storage, then decreased between 1 to 3 wk of storage. CaA increased L * and hue values of apple slices, suggesting CaA reduced browning, even in irradiated samples. The microflora population of apples slices was not affected by CaA, and CaA treatment did not alter the reduction in microflora by irradiation. The combination of CaA and irradiation enhanced microbial food safety while maintaining quality of fresh-cut apple slices.     

Effect of alternating magnetic field on the quality of fresh-cut apples in cold storage

This study evaluated the inhibitory effect of alternating magnetic field (MF) on enzymatic browning, physicochemical properties and microbial proliferation of fresh-cut apples during cold storage. The results showed that after 9-day storage, the browning index of apple slices increased by 174.07% in the conventional refrigerated group but by only 132.32% in the alternating MF group, the total number of colonies in the alternating MF group was 1.32 log CFU g⁻¹, less than that in the conventional refrigerated samples. The soluble solids and firmness of the MF group were 16.47% and 28.79% higher than those of the control group. The alternating MF significantly inhibited the activities of polyphenol oxidase (PPO) and peroxidase (POD) and exerted a significant effect on the tertiary structure of enzymes. Except for maintaining the good sensory quality, the MF also suppressed the growth of microorganisms in fresh-cut apples and extended their shelf life by at least 2 days.     

茉莉酸甲酯对鲜切苹果生理生化变化的影响

为研究茉莉酸甲酯(MeJA)对鲜切苹果生理生化变化的影响,将1cm3的鲜切富士苹果分别放入100、400、1600μmol/L的茉莉酸甲酯溶液中浸泡30min,包装后放入5℃冷库中贮藏。每2d测定各类酶活性以及与成熟衰老相关的指标等的变化。结果表明,经茉莉酸甲酯处理后,鲜切苹果的APX活性降低,但LOX、PAL、CAT、PPO、POD活性增加,相对电导率和丙二醛含量降低,说明茉莉酸甲酯处理启动了鲜切富士苹果的防御反应,导致相关防御反应的关键酶活性升高,从而降低机械伤害引发的自由基对细胞膜产生的伤害。研究认为,鲜切苹果贮前经适当浓度的茉莉酸甲酯溶液浸泡,可显著延长贮藏期和保持新鲜品质。     

Development and Characterization of a Baked Snack from Rings of Green Apples

Apple snacks were developed from green apple (Granny Smith) by baking. The effect of several pretreatments on properties such as color, texture, moisture, and water activity was studied. Blanching with steam, impregnation with calcium salts (calcium carbonate/calcium lactate), impregnation with sugars (fructose and maltodextrin), and addition of ascorbic acid were some of the pretreatments used. The addition of calcium proved to be favorable since it caused a reduction in the porous structure of the apple tissue associated with a greater firmness. The optimum selection of pretreatments on the rings of green apples gave as a result a snack with a higher acceptability in the evaluated attributes (color, sour taste, sweetness, and texture). Irrespective of the composition of the used solution of sugars, moisture, water activity, and lightness (L) of the baked apple rings did not differ significantly. The antioxidant activity of the obtained snack increased compared to that of fresh fruit due to the addition of ascorbic acid. The ascorbic acid content of apple snacks also turned out to be higher than that of fresh apples.     

氧化白藜芦醇对鲜切苹果及果汁褐变的影响

为研究氧化白藜芦醇(oxyresveratrol,OXY)对苹果褐变的抑制作用,采用不同浓度的OXY对鲜切苹果、苹果汁进行处理,探讨在不同储藏阶段切片色度和果汁褐变度变化情况及OXY对苹果汁内多酚氧化酶(polyphenol oxidase,PPO)和过氧化物酶(peroxidase,POD)活性的影响。结果表明:OXY可改善苹果切片的感官品质,显著延缓切片L*值的降低(P<0.05),抑制a*、b*、ΔE值的升高(P<0.05)。同时,OXY还能显著降低苹果汁褐变度(P<0.05),显著抑制苹果汁内PPO和POD活性(P<0.05)。综上,OXY能有效抑制鲜切苹果片及苹果汁褐变,其作用机制可能是通过抑制苹果内PPO和POD活性实现。     

Design of apple snacks – A study of the impact of calcium impregnation method on physicochemical properties and structure of apple tissues during convective drying

Calcium impregnation methods (at atmospheric pressure, AI, or under vacuum, VI) followed by air drying at 60 °C were used for producing healthy apple snacks. This study compared the effect of the impregnation method on the ultrastructure features and physicochemical properties (desorption isotherm, density, porosity and shrinkage, thermal transitions, rheological behaviour, colour) of fortified apples along convective drying. Calcium concentration in AI and VI dried apples were ≈ 3600 and ≈ 5200 ppm respectively, which implied, considering a portion of dried apple of 50 g, 18% and 26% of the recommended intake for adults. Calcium incorporation did not affect the desorption behaviour but induced browning of apple tissues. Drying resulted in a great increase in porosity of AI samples and a noticeable compaction of the VI tissues. Impregnated tissues at a_w ≤ 0.47 exhibited distinctive mechanical properties: AI apples were characterized by very high stiffness and lower resistance to rupture, while VI apples appeared stronger and moderately stiff.Industrial relevance textThis study will help to develop large-scale commercial production of calcium fortified apple snacks with distinctive characteristics. High quality and content of nutrients, easy industrialization and storage and a long shelf life are important aspects of these healthy snacks. They constitute a valuable functional shelf-stable product, that also can help feeding the population during natural disasters and wars, as well as reducing food insecurity in vulnerable groups as part of the diet. On the other hand, the use of apples not meeting the organoleptic requirements for direct consumption, or not processed into juice, drink, or cider as raw material, looks of particular interest for diversifying the production within the framework of sustainable production.     

紫外线照射与柠檬酸处理对鲜切苹果的保鲜作用

目的研究柠檬酸、紫外线照射、柠檬酸和紫外线照射联合处理对鲜切苹果生理生化的影响。方法以富士苹果为实验材料,分成4组,分别是0.5%柠檬酸(CA)溶液中浸泡5 min、紫外照射(UV)5 min/面、0.5%柠檬酸溶液中浸泡5 min+紫外照射(CA+UV)5 min/面、不处理的对照组(KB)。分别于0、1、3、5、7、10、13、15 d测定鲜切苹果的色差、多酚氧化酶(PPO)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)活性。结果富士苹果经过切分后,褐变严重。PPO、POD活性升高,PAL活性变化曲折,总体呈上升趋势。柠檬酸、紫外、柠檬酸和紫外联合处理的3三种处理方式都可以抑制鲜切苹果的褐变,降低PPO、POD、PAL的活性。在4种处理方法比较中,柠檬酸和紫外联合处理的效果比较好。结论柠檬酸和紫外联合处理是鲜切苹果的理想的保鲜方法。     

Effect of pH on the survival of Listeria innocua in calcium ascorbate solutions and on quality of fresh-cut apples

Fresh-cut apple slices were dipped in calcium ascorbate (CaA) solution at pH values ranging from 2.5 to 7.0 to inhibit browning. After treatment, the cut apples were stored at 4 and 10 degrees C for up to 21 days. Color and texture of the apples were determined on days 1, 14, and 21. In a separate experiement, the pH of CaA solution was adjusted with acetic acid to six different pH levels, and the solution was inoculated with Listeria innocua. The survival of the bacterium and the stability of CaA were determined at 0, 20, and 96 h. The cut apples maintained fresh quality when the pH of the CaA solution was above 4.5, but slight discoloration of apple slices dipped in pH 4.5 solution was observed after 14 days at 10 degrees C. At pH 5.0, the CaA dip maintained the quality of the apples at both temperatures for at least 21 days. The L. innocua population was reduced by 4 to 5 log CFU/ml at pH 4.5 after 96 h. At pH 5, the bacterial population in the CaA solution was reduced by approximately 2 log CFU/ml during the same period. The CaA solution was stable at pH 5 for at least 96 h. Reduction of the pH to between 4.5 and 5.0 might reduce the risk of foodborne illness due to consumption of fresh-cut apples treated with a CaA solution contaminated with Listeria.