Measuring Netted Muskmelon Maturity by Delayed Light Emission

Netted muskmelon fruits of Hale's Best, Magnum 45 and Saticoy cultivars in 6 different maturity classes, from immature to mature were examined. Maturity class was based on days after anthesis. The melons were evaluated for differences in delayed light emission (DLE) measurements and physical and chemical properties that relate to maturity. DLE, firmness, and chlorophyll decreased with increasing maturity, whereas Hunter a and soluble solids increased. DLE correlated highly (r =?0.94) with a calculated maturity index, indicating that DLE could be used as a nondestructive technique for measuring the maturity of netted muskmelon.     

NONDESTRUCTIVE MEASUREMENT OF CANARY MELON MATURITY BY DELAYED LIGHT EMISSION1

Canary melons (cv. Juan Canary) representative of the full range of maturities were evaluated in 1988 and 1989 for differences in delayed light emission (DLE) measurements and physical and chemical properties that are related to melon maturity. DLE, chlorophyll, yellow pigments and firmness decreased with maturity and soluble solids increased. DLE correlated highly (r = 0.85) with maturity index (MI), which was calculated for each melon based on values for chlorophyll, yellow pigments and soluble solids content. The high correlation of DLE with MI indicates that DLE could provide a nondestructive method for measuring the maturity of canary melons.     

Measurement of Tomato Maturity by Delayed Light Emission

Tomatoes were classified into three stages of maturity on the basis of visual color appearance and evaluated for differences in intensity of delayed light emission (DLE) and chlorophyll and carotenoid pigment contents. High correlations between DLE and chlorophyll show that as tomatoes ripened, DLE intensity and chlorophyll decreased and carotenoids increased. Results showed that DLE has a high potential for use in the automated sorting of fresh market tomatoes into categories of maturity.     

Delayed Light Emission as an Indicator of Cantaloupe Maturity

Saticoy cantaloupes at six stages of maturity were evaluated for differences in delayed light emission (DLE), chlorophyll, and soluble solids. DLE varied significantly and predictably by stage of maturity indicating its potential as a rapid, nondestructive method for measuring cantaloupe maturity.     

Measurement of Papaya Maturity by Delayed Light Emission

Papaya at five stages of maturity were evaluated for differences in intensity of delayed light emission (DLE), chlorophyll, β-carotene and Hunter color values. Results showed there were high correlations between DLE intensity and chemical and physical properties that relate to papaya maturity. DLE has a high potential as a rapid screening technique for identifying papayas which are one-half ripe and riper.     

脉冲强光在食品工业中的研究和应用进展

脉冲强光是一种非热物理杀菌新技术,利用氙气灯瞬时高强度、广谱的脉冲光来杀灭固体表面、气体和透明液体中营养细菌及芽孢、真菌和真菌孢子、病毒和原生动物等腐败病原微生物,具有能耗低、杀菌效率高、对产品质量和营养的负面影响较低等优点。本文综述了脉冲强光设备的工作原理、杀菌机理、杀菌影响因素及在果蔬、食品包装材料、水处理等中的研究和应用进展。     

Nondestructive Evaluation of Japanese Persimmon Maturity by Delayed Light Emission

Japanese persimmon cultivars (3 nonastringent, Fuyu, Jiro and Ichi Kijiro and 2 astringent, Aizumi Shiraza and Giambo) were evaluated during maturation for changes in delayed light emission (DLE) and physical and chemical properties relating to maturity. Firmness, chlorophyll and DLE decreased during ripening and Hunter a values, soluble solids and β-carotene increased. For all cultivars the relationship between DLE and maturity, indicated by calculated maturity index, was linear and negative. High correlations between DLE and maturity indicated that DLE has high potential for use as a rapid, nondestructive technique for estimating persimmon maturity.     

Delayed Light Emission as an Indicator of Peach Maturity

Delayed Light Emission as an Indicator of Peach Maturity. W. R. Forbus, Jr. and G. G. Dull. USDA-ARS, Richard B. Russell Agricultural Research Center, P. O. Box 5677, Athens, GA 30613. Keystone, Loring, and Nectar peaches were evaluated to determine relationships between delayed light emission (DLE) and physical and chemical properties that have been shown to be related to peach maturity. Results showed that DLE was highly correlated with average maturity rank (r = 0.96) for all three cultivars. DLE can provide an effective, nondestructive technique for measuring peach maturity.     

Nondestructive evaluation of the changes of total flavonoid,total phenols,ABTS and DPPH radical scavenging activities,and sugars during mulberry (Morus alba L.) fruits development by chlorophyll fluorescence and RGB intensity values

The use of chlorophyll fluorescence measurements and RGB intensity values to noninvasively evaluate changes of the internal chemical parameters (total flavonoid, total phenols, ABTS cation and DPPH radical scavenging activities and sugars) was investigated during all the development stages (ST) and the last four development stages of mulberry fruits in this study. The appropriately fitted relationships in this study revealed that chlorophyll fluorescence and RGB intensity have high correlations with the internal chemical parameters of mulberry fruits. Especially, each of the internal chemical parameters has higher correlations with chlorophyll fluorescence and RGB intensity during the period of ST4–ST7 than during the period of ST1–ST7 respectively. High correlations between chlorophyll fluorescence and the internal chemical parameters were found during the period of ST4–ST7, with R² ranged from 0.82 to 0.94. RGB intensity values showed fine correlations with the internal chemical parameters with R² ranged from 0.93 to 0.97 during the period of ST4–ST7. Therefore, chlorophyll fluorescence and RGB intensity values may be potential methods for quality evaluation of mulberry fruits during development, however, it is of great importance to select the most adequate parameter for the evaluation of different chemical components.     

Quantitative evaluation and prediction for preservation quality of cold shocked cucumber based on entropy

To evaluate and predict preservation quality of cold shocked cucumber and study the effects of cold shock parameters on the preservation quality, several entropy-based models were proposed. Cucumbers were cold shocked at different temperatures (0, 3, 6 °C) for different durations (20, 40, 60 min), and their preservation quality was evaluated by the proposed models. Results show that, the evaluation model can objectively evaluate preservation quality of cold shocked cucumber, and cold shocked at 3 °C for 40 min gets optimal preservation effect. Cold shock treatments at 0 °C and 3 °C improve preservation quality of cucumber effectively, while that at 6 °C fails. Therefore, entropy change caused by cold shock treatment should be higher than a certain critical value to improve preservation quality of cucumber effectively, and the duration is crucial for preservation quality when meeting this condition. The composite entropy change (S*) shows effect of both temperature and duration and characterizes cold shock intensity, and proposed prediction model of cold shock preservation quality can predict preservation quality of cucumber cold shocked at different temperatures and durations well.Industrial relevanceFresh fruits and vegetables contain rich essential substances to our bodies and play an active role in improving people's health. Since it has obvious seasonal regional characteristics on the fruits and vegetables production, pretreatment is very important for prolonging their storage periods. Cold shock treatment for many fruits and vegetables indicate that this method can effectively improve their preservation quality and have broad application space.This study lies in providing a series of methods based on entropy to characterize the cold shock intensity to fruits and vegetables, carrying out objective quantitative evaluation and prediction for preservation quality of the cold shock treatment, and based on which, the influence mechanism of cold shock intensity (temperature and duration) on preservation quality of fruits and vegetables was analyzed. The results will contribute to better design and optimization of the cold shock process for postharvest fruits storage.     

清洗技术对鲜切果蔬微生物与品质影响的研究进展

清洗是鲜切果蔬加工过程中必不可少的环节,清洗不仅可以减少微生物数量,还可以去除果蔬经切分后流出的组织汁液,减缓褐变反应,降低营养成分损失,提高食用品质。本文综述了物理清洗、化学清洗和生物清洗技术通过物理或化学作用破坏微生物细胞壁、细胞膜和DNA等而导致其死亡的杀菌机理及其对鲜切果蔬中PPO和POD等褐变相关酶活的抑制作用以及这些技术对鲜切果蔬中V_C、叶绿素和固形物含量等营养物质的维持效果,同时还归纳了适合不同种类鲜切果蔬的清洗技术条件,提出了鲜切果蔬清洗技术的研究方向,以期为今后研究不同清洗技术对鲜切果蔬微生物与品质的影响提供理论依据。     

Gloss Evaluation of Curved-surface Fruits and Vegetables

Gloss measurements are used to evaluate the quality and appearance of a product, especially in cases where esthetic appearance is of importance. Most commercial glossmeters are designed for measuring products of flat surface and therefore are not suitable for food products because of their uneven, curved surface. A new generation of commercial glossmeters is recently available for confined areas, curved surfaces, and surfaces that are not uniform. This article provides a brief review of gloss measurement principles and methods for fresh fruits and vegetables. It reports on the gloss measurement of apples and other fresh products using a commercial glossmeter and a specially designed spectrometer-based gloss measurement prototype integrated with imaging and automatic sample positioning capabilities. Results showed that the prototype had a nonlinear relationship with standard gloss measurements. With the new setup, the gloss of apples was measured with the repeatability for 90% of the measurements being better than 16%, calculated as the ratio of the difference between maximum and minimum gloss values to the mean value in percent. Further research is needed to simplify the imaging/mechanical configuration and improve the coordinate calculation algorithm to achieve more accurate, repeatable gloss measurements.     

植物生长调节剂在果蔬中的应用与安全性分析研究进展

植物生长调节剂可有效提高果蔬产量、品质,其在果蔬生产中的应用越来越多;对植物生长调节剂残留危害风险的评估也成为了研究热点。本文综述了植物生长调节剂的主要类别、作用和在果蔬中的应用现状;并归纳分析了果蔬中多效唑、氯吡脲、赤霉酸、乙烯利、2,4-二氯苯氧乙酸（2,4-D）等几种主要生长调节剂的危害和残留现状;发现果蔬中乙烯利的平均残留量最高,葡萄、豆芽、草莓等果蔬中植物生长调节剂残留情况最为严重,其潜在的安全隐患应引起重视;而国家现行植物生长调节剂标准中并未覆盖一些果蔬,亟需完善植物生长调节剂残留相关标准及风险评估。     

Effect of Thermal and Nonthermal Processing on Textural Quality of Plant Tissues

In the current fast revolving world, the consumption of processed food is increasing drastically. The population who depend on these processed foods are also cautious about the quality and safety of what they consume. This being the case, in order to satisfy the consumer it is the responsibility of the researcher and the manufacturer to check what happens to food on processing. Plant-derived foods such as fruits and vegetables are sensitive producers which are to be handled cautiously through each steps involved in processing, starting from harvest to storage, processing to package, transportation to distribution, till it reaches the consumer. During processing, the plant materials, which are made up of complex structural components such as lignin, cellulose, pectin, etc. undergo changes which has its effect on the quality attributes of the final product. Texture is an important quality parameter of all the sensory properties. The relation between the structure of the plant tissue and the texture of the final product is reviewed in this paper comprehensively.     

植物精油的抑菌活性及在鲜切果蔬中的应用

鲜切果蔬由于具有营养、新鲜、方便等优点,受到越来越多消费者的喜爱。鲜切果蔬中致病菌和致腐菌是影响鲜切果蔬品质的重要因素,植物精油作为天然来源的抑菌物质,对鲜切果蔬产品具有防腐保鲜、维持品质等作用。本文介绍了植物精油的抑菌活性及作用机理,并综述植物精油对鲜切果蔬产品防腐、品质控制等方面的研究进展,同时对其在鲜切果蔬应用中存在的问题和应用前景进行了展望,为植物精油保鲜剂的开发提供了理论依据。      

新型加工食品果蔬纸研究进展

果蔬纸是一种新型的果蔬深加工产品,可作为休闲食品或可食性包装材料。果蔬纸能保留基料果蔬原有的香味、色泽和各种营养成分,是一种能提高果蔬附加值的新型加工产品。本文从果蔬纸原料配方和关键加工工艺方面论述果蔬纸研究的进展,从感官品质、营养品质、贮藏品质、抗菌特性等方面论述果蔬纸品质的研究状况,还就目前果蔬纸加工及品质研究中存在的问题(如新产品开发、纸质特性欠佳、制浆与护色关键工艺需要优化等)进行了分析,并提出了解决这些问题的建议,以期为果蔬纸的开发研究提供参考。     

茉莉酸甲酯诱导的采后果蔬抗病性及其机制研究进展

茉莉酸甲酯(methyl jasmonate, MeJA)是一种广泛存在于植物中的天然植物激素,参与植物的许多代谢过程包括生长、发育、成熟、衰老、抵御生物和非生物胁迫等。由病原真菌侵染引起的果蔬采后病害是导致果蔬贮藏和运输过程中品质劣变和腐烂的原因之一,不仅对生产者和消费者造成巨大经济损失,还会在组织体内产生危害人体健康的有毒次生代谢产物。因此,开发绿色安全的果蔬采后病害控制技术具有重要意义。本文总结了采前和采后MeJA单独或与其他物理、生物方法复合处理对果蔬采后主要真菌性病害的控制作用,并从活性氧代谢、病程相关蛋白的积累、苯丙烷代谢、多胺代谢、能量代谢、细胞壁物质代谢、转录调控等方面详细阐述了其诱导抗性机制,以期为MeJA广泛用于控制果蔬采后病害提供实践参考和理论依据。     

促进植物内源性果胶甲酯酶催化作用的因素与机制及其在果蔬加工中的应用

植物内源性果胶甲酯酶（pectin methylesterase,PME）存在于天然植物组织中,可以催化高酯果胶脱甲基酯化生成低酯果胶,进而影响果蔬硬度、出汁率等质构及加工品质。一方面,为了避免贮藏期间出现果蔬汁浑浊沉淀、果蔬罐头中果肉变软、调味酱（如辣椒酱）中皮肉分离等不良品质,会在加工过程中抑制PME活性;另一方面,为了提高果蔬汁出汁率、生产低酯果胶等,也可在食品中添加外源PME。目前,对于通过激活内源PME来改善食品加工的研究较少,因此,本综述重点讨论促进植物内源性PME催化作用的因素与机制及其在果蔬贮藏加工中的应用,为植物内源性PME在果蔬加工中的充分利用提供理论参考。     

蔬干燥前处理技术的应用及研究进展

目前,针对果蔬干制加工中存在的能耗高、时间长、营养成分损失严重等问题,主要通过干燥技术的创新以及干燥设备的研发予以不断改善,而干燥前处理技术在国内发展相对缓慢。干燥前处理技术是指通过物理、化学、生物等技术手段对物料进行处理,从而起到加快物料干燥速率、提高产品外观及营养品质、延长货架期的作用。目前常用的果蔬干燥前处理技术有:热烫、冻融、渗透、化学试剂、超声、超高压、高压脉冲电场、二氧化碳浸渍处理等。本研究针对上述几种前处理技术的原理、特点进行综述,对比不同前处理技术的作用机制及适用果蔬的种类,并展望了不同前处理技术的发展前景与趋势,以期为果蔬干燥新技术的研究与开发提供指导意见。     

茉莉酸甲酯对果蔬抗性、抗氧化活性及品质影响的研究进展

茉莉酸甲酯作为与抗损伤相关的植物激素和信号分子,外源应用可激发植物防御基因的表达,诱导其产生与机械伤害相似的防御效果。采后果蔬在贮藏和运输期间总酚、抗坏血酸以及谷胱甘肽等抗氧化物质含量下降,致使其抗氧化活性降低,且品质和抗性受到了不良影响,大大缩短了果蔬的货架期,造成了一定的经济损失。研究发现茉莉酸甲酯可通过提高果蔬抗性物质合成酶和抗氧化相关酶的活性增强果蔬抗性,有效维持果蔬的抗氧化活性、降低品质损失、延长货架期。本文对近些年国内外茉莉酸甲酯在果蔬应用上的研究进展进行了综述,聚焦于其对果蔬抗性、抗氧化活性及品质等方面的影响及作用机理,为今后茉莉酸甲酯在果蔬保鲜上的研究及应用提供参考。