真空浸渍辅助L-半胱氨酸处理对贮藏期鲜切马铃薯的护色作用

为研究L-半胱氨酸(L-cysteine,L-cys)对鲜切马铃薯的抗褐变机制,以鲜切马铃薯为研究对象,采用真空浸渍技术辅助0.7 g/L的L-cys溶液处理鲜切马铃薯,分析贮藏期鲜切马铃薯褐变指数(browning index,BI)、多酚氧化酶活性(polyphenol oxidase,PPO)、过氧化物酶活性(peroxidase,POD)、苯丙氨酸解氨酶活性(phenylalanineammonialyase,PAL)、总酚含量及抗氧化活性的变化。结果表明,在贮藏期,试验组鲜切马铃薯BI值、PPO活性、POD活性、PAL活性均显著低于对照组(p<0.05)。试验组总酚含量在贮藏0~6 d,显著低于对照组(p<0.05),但贮藏后期则显著上升(p<0.05)。另外,两组鲜切马铃薯抗氧化活性在贮藏期,均呈先上升后下降趋势。因此,结果表明,L-cys处理可以抑制鲜切马铃薯酶活性,从而延缓鲜切马铃薯在贮藏期间的褐变。     

鲜切马铃薯复合褐变抑制剂组合的筛选

利用二次旋转组合设计筛选能取代亚硫酸盐的鲜切马铃薯复合褐变抑制剂组合,分析其对鲜切马铃薯贮藏期间PPO活性和褐变度的影响。结果表明,马铃薯切片最佳复合防褐剂配方组合为0.005%曲酸＋0.045%异抗坏血酸钠＋0.045%半胱氨酸(L-Cys)＋0.01% CaCl2＋0.2992% EDTA-2Na。该褐变抑制剂能够显著抑制鲜切马铃薯贮藏期间PPO活性,整个贮藏期间推迟PPO活性高峰时间6d以上;对鲜切马铃薯组织的褐变有明显延缓作用,处理组感官效果明显优于亚硝酸盐处理组和蒸馏水对照组,可以替代亚硫酸盐作为防褐剂用于鲜切马铃薯的生产和流通环节。     

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。     

Ascorbic acid enrichment of whole potato tuber by vacuum-impregnation

The aim of this study was to evaluate the use of vacuum-impregnation (VI) for enriching the ascorbic acid content of whole potatoes. Whole potatoes were immersed in a 10% ascorbic acid (AA) solution. A vacuum pressure of 70 cm Hg was applied for 0–60 min, following atmospheric pressure restoration for 3 h, while samples remained in the VI solution. AA concentrations of potatoes were measured using HPLC. The effects of cooking and storage time in subsets of the fortified samples were also evaluated. Results indicated that the AA concentration of whole potatoes increased with vacuum time (max 150 mg/100 g fr. wt.). In addition, a steam-cooking study showed that 100 g of the 25 min steam-cooked VI potatoes could provide adults with 90–100% of the recommended daily allowance of AA (100 mg). The storage study showed that VI whole potatoes had a relatively high AA concentration (50 mg/100 g fr. wt.), even at 14 days of storage at 4 °C. This study indicated that VI treatment of whole potatoes was useful for enriching the AA content.     

短波紫外线处理对贮藏期鲜切马铃薯的护色作用

为研究短波紫外线(ultraviolet-C,UV-C)对贮藏期鲜切马铃薯的护色作用,在输出功率为15 W条件下对鲜切马铃薯辐照处理6 min.检测0～12 d贮藏期内褐变指数(browning index,BI)、多酚氧化酶(polyphenol oxidase,PPO)活性、过氧化物酶(peroxidase,POD...     

Retention of Fortified Vitamin E and Sensory Quality of Fresh-Cut Pears by Vacuum Impregnation With Honey

ABSTRACT:  Our hypothesis was that the incorporation of vitamin E into honey-based vacuum impregnation (VI) solution could be a novel approach to develop high-quality and vitamin E-fortified fresh-cut pears (D'Anjou). A 20% diluted wildflower honey VI solution was used with 0.4% to 0.8%α-tocopherol from 3 different sources: α-tocopherol-acetate (VE-acetate), free α-tocopherol (V-OH), or water-soluble α-tocopherol-acetate (VE-H₂O) for nutritional fortification of the pear slices. Fresh-cut pear slices were immersed in VI solution and subjected to a vacuum at 100 mm Hg for 15 min following atmospheric restoration for 30 min. Samples were stored at 2 °C and 88% relative humidity up to 2 wk for nutritional, physiochemical, and sensory quality evaluations. Vitamin E content of pears impregnated with honey solution containing VE-acetate, VE-OH, or VE- H₂O increased 80 to 100 times and 65% to 80% VE activities were retained during 2 wk storage. Microbial counts were under 2.6 log colony forming unit(CFU)/g pear at the end of 7 d storage, significantly lower than the industrial standard. Instrumental color analysis and sensory evaluation indicated that VE fortified pear slices had significantly higher lightness, lower browning index, and higher consumer acceptance rating than control (unfortified) ones. There is a strong Pearson correlation between instrumental analysis and consumer sensory evaluation in pear color. This study demonstrated a great potential for developing high-quality, vitamin E-fortified fresh-cut pears by use of VI technology with honey, thus further enhancing the health benefit of pears.     

静电场协同阻隔性包装对鲜切马铃薯贮藏过程中品质的影响

为了延长鲜切马铃薯的货架期,采用静电场处理与阻隔性材料真空包装相结合的方式贮藏鲜切马铃薯。以新鲜马铃薯切片为试材,以感官、白度值、褐变度、失重率、可溶性固形物含量及V_C含量为评价指标,选用高阻隔性材料尼龙/聚乙烯(polyamide/polyethylene,PA/PE)复合膜、聚乳酸(Poly(L-lactic acid),PLLA)薄膜进行真空包装及无任何包装的空白组为对照,分别置于电场和无电场两组环境贮藏,均设4℃、85%相对湿度。结果显示,通过单一变量对比分析发现,同种包装材料下,电场环境下的鲜切马铃薯褐变减缓,失重率减慢,在空白组中,施加电场贮藏下的马铃薯失重率可减少30%。而同一贮藏环境下,阻隔性相对较高的PA/PE膜所包装的样品较另外两组能更好地延缓褐变和减少失水。综合静电场和高阻隔包装的电场-PA/PE组保鲜效果最佳,贮藏期间反应色泽的指标白度值和褐变度始终优于其他组,失重率最小,贮藏第15 d时感官评分为6分,而其他组则均低于6分失去食用价值,并较好的保持了V_C含量及可溶性固形物的含量。     

鲜切甘薯高效化学褐变抑制剂组合的筛选

试验筛选了鲜切甘薯能取代亚硫酸盐的化学褐变抑剂组合,分析了其对甘薯贮藏期间PPO活性和褐变度的影响。研究结果表明0.2%L-Cys+0.30%CA+0.15%EDTA-2Na+0.30NaCl组合抑制褐变效果最好,各因素对鲜切甘薯抑制褐变效果的主次顺序为A>B>C>D。该褐变抑制剂组合能够显著抑制鲜切甘薯贮藏期间PPO活性,对鲜切甘薯组织的褐变有明显延缓作用。     

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.     

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。     

INTERACTION EFFECTS BETWEEN ASCORBIC ACID AND CALCIUM CHLORIDE IN MINIMIZING BROWNING OF FRESH-CUT GREEN BANANA SLICES

Dopamine level of three banana varieties was determined by spectrophotometry. Dwarf Cavendish banana had the highest browning potential and was used for processing into fresh-cut slices. The slices were treated with anti-browning agents, packed at 55% vacuum level and stored at 10C. A 2  ×  3 factorial treatment structure was used to investigate the interaction effects between ascorbic acid and calcium chloride. At three-day intervals, physico-chemical parameters were investigated. The interaction effect between ascorbic acid and calcium chloride for lightness and redness was significant ( P <  0.05); however, these color parameters were mainly driven by the main effect of ascorbic acid ( P <  0.01). The interaction effect between ascorbic acid and calcium chloride and the main effect of each chemical on firmness were highly significant ( P <  0.01). There was no interaction effect on yellowness ( P >  0.05). Browning and loss of firmness were promoted when 4% calcium chloride was used singly and minimized when 2% ascorbic acid was added.

PRACTICAL APPLICATIONS

Green bananas are widely used in many cooking dishes and utilized in the manufacture of several industrial food products like banana flour, deep-fried chips and baked banana crisps. However, one of the major limitations of green peeled bananas as a raw material, to successfully penetrate the market, is the excessive enzymatic browning after peeling. This badly affects the product's color and decreases the quality of the produce. A combination of naturally occurring substances, calcium chloride (2%) and ascorbic acid (2%) significantly minimized enzymatic browning of green peeled bananas under partial vacuum packaging, while retaining the firmness of the produce and maintaining a shelf life of 12 days at 10C.     

异抗坏血酸与氯化钙联合处理对鲜切芒果的保鲜效果

为研究异抗坏血酸与氯化钙联合处理对鲜切芒果保鲜效果的影响,鲜切芒果在1 g/100 mL异抗坏血酸和0.5 g/100 mL氯化钙的混合溶液中浸渍处理5 min后,4℃相对湿度80%条件下贮藏15 d,每天取样测定呼吸速率,每3 d测定细胞膜相对渗透率、硬度、可滴定酸、类胡萝卜素、抗坏血酸(AsA)、总酚、褐变指数、超氧阴离子(O₂-·)产生速率、抗氧化酶及多酚氧化酶(PPO)活性等指标。结果表明:与对照相比,异抗坏血酸+氯化钙联合处理使鲜切芒果的呼吸峰值降低了41.20%,并延缓相对渗透率升高和硬度下降;保持较高的类胡萝卜素、AsA含量,维持总酚含量相对稳定,在贮藏前期保持了较高的可滴定酸含量,减少褐变发生;降低了O₂-·产生速率,明显抑制PPO的活性,提高超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性,并且在0~9 d时延缓过氧化物酶(POD)的下降,但在贮藏后期降低了POD的活性。以上结果表明异抗坏血酸+氯化钙联合处理可以保持鲜切芒果较好的贮藏品质,延缓膜透性增加并提高活性氧(ROS)的清除能力,从而延缓衰老,抑制褐变。     

Combined Vacuum Impregnation and Electron‐Beam Irradiation Treatment to Extend the Storage Life of Sliced White Button Mushrooms (Agaricus bisporus)

This study assessed the application of an antibrowning solution using vacuum impregnation (VI) and then electron‐beam irradiation as a means to extend the shelf life of sliced white button mushrooms (Agaricus bisporus). A preliminary study helped to determine the best antibrowning solution and VI process parameters. Mushroom slices were impregnated with 2 g/100 g ascorbic acid + 1 g/100 g calcium lactate; 2 g/100 g citric acid + 1 g/100 g calcium lactate; 1 g/100 g chitosan + 1 g/100 g calcium lactate; and 1 g/100 g calcium lactate at different vacuum pressures and times and atmospheric restoration times. Selection of the antibrowning solution and VI parameters was based on texture and color of the mushroom slices. Next, the slices were irradiated at 1 kGy using a 1.35‐MeV e‐beam accelerator. Physicochemical, sensory, and microbial quality of mushrooms was monitored for 15 d at 4 °C. The best impregnation process in this study was 2 g/100 g ascorbic acid and 1 g/100 g calcium lactate at 50 mm Hg for 5 min and an atmospheric restoration time of 5 min. The control (untreated) samples suffered structural losses throughout storage. Only the vacuum impregnated‐irradiated samples had acceptable color by the end of storage. Sensory panelists consistently preferred the samples produced with VI and irradiation because exposure to ionizing radiation inhibited growth of spoilage microorganisms.     

热水处理对鲜切马铃薯生理和品质的影响

以鲜切马铃薯为试验材料,研究鲜切马铃薯在35℃10 min的热水处理和对照组(CK)下生理指标和品质指标的变化。结果表明:在低温(4℃)贮藏条件下,35℃10 min的热水处理显著抑制了鲜切马铃薯的失重率和呼吸强度,维持了较高的白度和可溶性固形物含量,有效地保持了细胞膜的完整性,抑制了多酚氧化酶(PPO)和过氧化物酶(POD)的活性,从而改善了鲜切马铃薯的贮藏品质,延缓了鲜切马铃薯的褐变。     

Heated Ascorbic/Citric Acid Solution as Browning Inhibitor for Pre-Peeled Potatoes

Treatment of pre-peeled potatoes with heated ascorbic acid (AA)/citric acid (CA) solution to extend shelf-life was investigated. Potatoes were abrasion or high pressure steam peeled, heated for 5–20 min in 1% AA + 2% CA at 45–55°C cooled, and then dipped for 5 min in browning inhibitor (BI) solution containing 4% AA +1% CA +1% sodium acid pyrophosphate. Combined treatment inhibited potato discoloration for 14 days at 4°C compared to 3–6 days with BI treatment alone. Raw material and treatment conditions were selected to minimize graying and textural abnormalities encountered with some treatments. Treatment with heated AA/CA may be an alternative to use of sulfites to control browning in pre-peeled potatoes.     

抗坏血酸与壳聚糖处理对鲜切香芋贮藏效果的研究

以湖南香芋头为试材,研究不同浓度抗坏血酸与壳聚糖处理对鲜切香芋的贮藏效果及生理生化变化的影响。结果表明,在15℃贮藏温度下,与对照相比,0、1.0、5.0、10.0g/L 抗坏血酸(VC)分别与15.0g/L 壳聚糖配合处理较好地保持了鲜切香芋的外观和营养,减少鲜切香芋的失重率和褐变度,并抑制多酚氧化酶(PPO)、过氧化物酶(POD)和淀粉酶的活性。其中,5.0g/L 抗坏血酸与壳聚糖配合处理的保鲜效果最明显。     

超高压处理对鲜切马铃薯质地及细胞壁多糖含量的影响

本文旨在探究鲜切马铃薯的质地随压力变化的规律及质地改变的机制。研究了超高压(HPP,100~600 MPa,10 min)对鲜切马铃薯色泽、硬度、咀嚼度、细胞壁相关酶活及多糖组成的影响。结果表明,HPP在压力≥ 500 MPa下对鲜切马铃薯的褐变抑制较好,300 MPa时褐变严重且程度高于空白。HPP相较传统热处理,能够更好的保持鲜切马铃薯的硬度及咀嚼度;但相比空白,HPP处理后硬度均有不同程度的下降,其中300 MPa时硬度下降最大,达到500 MPa时,硬度出现回升,咀嚼度在该压力下同样存在回升现象。HPP在一定程度上改变了马铃薯细胞壁相关酶活性及多糖含量,果胶甲酯酶(PME)活性在压力≤ 500 MPa具有稳定性,同时HPP可抑制多聚半乳糖醛酸酶(PG)和内切β-葡聚糖酶(Cx)活性,在压力100、500、600 MPa下提高β-葡糖苷酶及外切β-葡聚糖酶(C₁)活性;相比空白,HPP处理后鲜切马铃薯纤维素(CEL)、碱溶性果胶(NSF)、螯合性果胶(CSF)含量显著(P<0.05)提高,其中CSF含量在300 MPa下显著(P<0.05)低于空白水平,水溶性果胶(WSF)含量在100、600 MPa下显著(P<0.05)下降,其余压力下无显著变化,而经HPP处理后鲜切马铃薯半纤维素(HC)含量均显著(P<0.05)下降。经相关性分析,HPP处理后马铃薯硬度、咀嚼度与CSF、NSF、CEL含量呈显著或极显著正相关(P<0.05或P<0.01),与WSF含量呈极显著(P<0.01)负相关,与HC含量相关性不显著,PME活性对其质构指标影响较大。综上,超高压处理后细胞壁多糖组成及含量变化影响了鲜切马铃薯的质地。     

Impregnation Techniques for Aroma Enrichment of Apple Sticks: A Preliminary Study

The food industry often utilizes flavor-enriched, semifinished food products as ingredients in more complex preparations. To the best of our knowledge, there are no methods to produce minimally processed food items to which flavorings have been added. In this investigation, apple sticks were enriched with a green apple aroma using different techniques. In particular, vacuum impregnation (VI), ultrasound technology (USI), and the combination of these two techniques (VUSI) were compared with atmospheric pressure impregnation (AI). An isotonic solution of fructose containing ascorbic acid and green apple flavoring was used for impregnation of apple sticks. Different treatment times (2.5, 5.0, and 12.5 min) were investigated, and the relative amount of the major compounds of impregnation flavoring was recorded. Significant differences between treatments were detected: VI and VUSI gave the highest aroma enrichment at 5.0 min of treatment. Different impregnation behaviors were recorded for alcohols and esters: the former increased even after 5.0 min of treatment, and the other components increased until 5.0 min and then decreased, mainly when ultrasound was applied (USI and VUSI). Some possible explanations of these results are proposed, although additional studies are needed to explain the mechanisms involved.     

鲜切马铃薯褐变发生机理及其控制方法研究进展

随着人们生活水平的提高,鲜切果蔬凭借自身的优势开始进入人们的视线,鲜切马铃薯由于其丰富的营养和方便性被人们广泛应用。鲜切马铃薯在去皮和切割过程中,细胞组织结构会受到损伤,引发一系列的生理代谢变化,这些变化对马铃薯的品质质量及色泽都产生很大影响,最主要的是切割会诱导酶促褐变反应的快速发生,使鲜切马铃薯的外观品质迅速降低。本文综述了鲜切马铃薯褐变发生的机理,同时对国内外控制鲜切马铃薯褐变技术的方法进行归纳,总结了物理、化学等不同方法的研究进展并提出相应建议,为后续鲜切马铃薯的研究提供参考。     

Effect of Natural Antibrowning Agents on Color and Related Enzymes in Fresh-Cut Fuji Apples as an Alternative to the Use of Ascorbic Acid

ABSTRACT:  Polyphenoloxidase (PPO) and peroxidase (POD) were evaluated in fresh-cut Fuji apple slices and the effect of the individual or combined use of ascorbic acid, 4-hexylresorcinol, N-acetylcysteine, and glutathione on their respective activities was determined. Additionally, color changes during storage at 4 °C were measured throughout 14 d of storage. PPO activity increased with storage time and was inhibited by the individual use of N-acetylcysteine and glutathione. POD activity in the apple slices was effectively inhibited by the combined use of ascorbic acid with any of the other antibrowning agents. On the other hand, an individual treatment with 1% N-acetylcysteine helped in maintaining the color of fresh-cut apples during 14 d of storage, whereas the use of ascorbic acid was not enough to prevent color deterioration of the apple slices from the 1st day of storage. The results obtained corroborated the effectiveness of other natural antibrowning agents over the traditional use of ascorbic acid in the control of the enzymatic browning in the fresh-cut fruit industry.