Effect of minimal processing on bioactive compounds and color attributes of fresh-cut tomatoes

The feasibility of minimal processing and modified atmosphere packaging (5%O₂+5%CO₂) to preserve color attributes and bioactive compounds of fresh-cut tomato from different cultivars (Rambo, Durinta, Bodar, Pitenza, Cencara and Bola) was evaluated through storage under refrigeration. The phenolic compounds and vitamin C content of the six cultivars varied between 187.4 and 335.9 mg/kg fw and from 69.6 and to 212.3 mg/kg fw, respectively. The highest content of lycopene was found in Bodar tomatoes (80.5 mg/kg fw) while the concentration in the other cultivars ranged between 20.0 and 43.1 mg/kg fw. Antioxidant capacity, measured on the basis of the DPPH stable radical, was higher than 9.8% of DPPH inhibition. Neither the content of health-related compounds (lycopene, vitamin C and phenolic compounds) nor the antioxidant capacity changed significantly between whole and just-processed fresh-cut tomatoes. Furthermore the initial colors of fresh-cut tomatoes as well as vitamin C were maintained for 3 weeks under cold storage. The antioxidant capacity was well correlated with vitamin C and phenolic content, whereas lycopene was directly related to color measurements (a^*, L^* and H^*). Minimal processing maintains the main antioxidant compounds and color parameters of slices tomatoes for 21 days at 4 °C, thus preserving their initial nutritional value.     

辣椒籽中生物活性成分及其功能活性研究进展

对近年来国内外关于辣椒籽中的主要营养成分、生物活性物质以及主要功能活性的研究成果进行了综述,阐明了该领域的主要研究进展,为进一步开发利用辣椒籽资源提供参考依据和新的思路。     

Effect of hot-air drying on flavour compounds of bell peppers (Capsicum annuum)

The influence of hot-air drying on the composition of both volatile and non-volatile flavour compounds of different Dutch bell pepper cultivars was investigated. Contents of glucose, fructose, ascorbic, citric, and oxalic acid decreased significantly after drying, while the levels of sucrose, malic, fumaric, and cis-aconitic acid increased. Glucose, fructose and ascorbic acid probably participate in Maillard reactions during heating. Different effects of drying could be distinguished on the composition of volatile compounds. The majority of these compounds evaporated during drying. Some compounds were partly retained in the dried bell peppers, whereas others disappeared completely. Gas chromatography-sniffing port analysis revealed that compounds with mainly “fresh” odour notes like lettuce/grassy/green bell pepper ((Z-2-3-hexenal), fruity/almond ((E)-2-hexenal), fruity (octanal), lettuce/green bell pepper ((Z)-3-hexenol), and grassy/green bell pepper ((Z)-2-hexenal) decreased or disappeared after drying. Another group of compounds increased or were formed during drying, like 4-octen-3-one, (E)-2-heptenal, (E)-2-octenal, (E,Z)- and (E,E)-2,4-heptadienal, decanal, and (E)-2-nonenal; most are known as autoxidation products of unsatu-rated fatty acids. The increased levels of 2-methylpropionic and 2- and 3-methylbutyric acid, 2-metlhylpropanal, and 2- and 3-methylbutanal seemed to be due to Strecker degradation. Gas chromatography-sniffing port analysis showed that the latter three compounds had distinct cacao, sweaty, and spicy odour characteristics.     

Effects of light-emitting diode illumination on the quality of fresh-cut cherry tomatoes during refrigerated storage

The effects of light-emitting diode (LED) illumination on the quality of fresh-cut cherry tomatoes were investigated. Tomatoes were exposed continuously to red, green, blue and white LED light for 7 days and control samples stored in darkness. Results showed that blue light treatment significantly led to more total soluble solids, lycopene concentration and individual phenolic compounds (chlorogenic acid, caffeic acid, rutin) after 7 days of storage. On day-5, green and blue light-treated tomatoes showed relatively higher firmness than samples treated by other lights and the control. At the early stage of storage, blue light could preserve the fresh flavour of tomatoes compared to other treatments. Overall, the blue light was most effective in the quality preservation of fresh-cut cherry tomatoes and could be used as a novel strategy in the preservation of fresh-cut fruits and vegetables during shelf life.     

热激处理对鲜切甜椒活性氧代谢及贮藏品质的影响

为探讨热激处理鲜切甜椒的保鲜作用,对鲜切甜椒进行热水45、50、55℃分别浸泡10、4、1min处理后,于8℃冷藏期间分析了活性氧水平、抗氧化酶活性及品质指标。热激处理50℃4min和55℃1min,可抑制超氧阴离子（O-2）产生,减少过氧化氢（H2O2）含量,诱导提高超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性,抑制过氧化物酶（POD）活性,同时可以抑制丙二醛（MDA）积累,有效保持鲜切甜椒重量、叶绿素及可溶性蛋白质含量,55℃1min处理效果好于50℃4min处理。表明适宜的热激处理可通过调节活性氧代谢保持鲜切甜椒冷藏品质。      

Influence of processing on the antioxidant capacity and bioactive compounds in jellies from different blackberry cultivars

The effect of thermal processing and the berry cultivar has been the subject of several studies, to serve as a basis for the least possible loss of bioactive compounds and antioxidant capacity. In Brazil, there are numerous blackberry cultivars under cultivation, and in this context, the aim of this work was to study how the bioactive compound contents and antioxidant capacity of blackberry jelly were influenced by the cultivars (Guarani, Brazos, Comanche, Tupy, Cherokee, Caingangue and Choctaw). Analysis was made of 7 fresh blackberry cultivars and 7 blackberry jelly formulations. Analysis of antioxidant activity, total phenolics, total anthocyanins and ascorbic acid was performed. It was verified that the contribution of the heat sensitive antioxidants compounds is considerable in all blackberry cultivars, and the degradation of these compounds was significantly different between the different blackberry cultivars. The Brazos and Caingangue cultivars stand out as undergoing the lowest losses in processing, resulting in jellies richer in bioactive compounds and higher antioxidant capacity.     

响应曲面法研究热处理对鲜切荸荠品质的影响

以荸荠为原料,采取中心复合旋转实验设计,研究不同的热处理温度、热处理时间以及贮藏时间对鲜切荸荠冷藏过程中品质的影响。利用SAS9.0软件,通过响应曲面法建立热处理对鲜切荸荠脆性、失重率和抗坏血酸含量的二次多项数学模型,对其显著性、拟合程度等进行分析;同时利用模型的响应面对影响鲜切荸荠品质的关键因子及其相互作用进行了探讨。结果表明,影响鲜切荸荠脆性和抗坏血酸含量的关键因素是热处理温度和贮藏时间,影响鲜切荸荠失重率的关键因素是贮藏时间,热处理时间及其他交互作用对鲜切荸荠的这些品质影响不显著。     

Effect of storage on the bioactive compounds and antioxidant activity of quince nectar

The changes of bioactive components and antioxidant activity of quince nectar were determined during 9 months of storage at 5, 20, 30 and 40 °C. The amount of total phenolics, flavonoids and antioxidant activity was significantly declined during storage at all temperatures. Loss of L‐ascorbic acid at 5, 20, 30 and 40 °C was 32.08%, 43.69%, 65.21% and 88.82%, respectively. L‐ascorbic acid degradation was in accordance with the first‐order reaction kinetics, and activation energy was found as 43.65 kJ mol^?1. After 9 months of storage, Hydroxymethylfurfural (HMF) contents of quince nectars were 15.01, 16.64, 21.69 and 57.89 mg kg^?1 at 5, 20, 30 and 40 °C, respectively. HMF accumulation fitted a zero‐order kinetic model, and activation energy was found as 88.30 kJ mol^?1. A significant correlation was found among L‐ascorbic acid, total phenolics, flavonoids and antioxidant activity.     

乙醇处理对鲜切荸荠黄化及相关酶的影响

以荸荠为试材,研究10%、20%、30%和40%乙醇处理对鲜切荸荠黄化及相关酶的影响。结果表明:在贮藏期间,不同浓度乙醇处理均不同程度地抑制了鲜切荸荠L*值的下降。随着乙醇浓度增加,b*值和C*值上升幅度均逐渐减小。与此相对应,鲜切荸荠组织内柚皮素和圣草酚含量的增加均随乙醇浓度增加而减小。同时,鲜切荸荠内苯丙氨酸解氨酶（Phenylalanine ammonia lyase,PAL）、查尔酮异构酶（Chalcone isomerase,CHI）和类黄酮3’-羟化酶（Flavonoid3’-hydroxylase,F3’H）活性变化趋势随乙醇浓度增加均逐渐减缓。总之,不同浓度乙醇对控制鲜切荸荠组织黄化均有一定效果。其中,10%和20%的乙醇处理在短期内作用效果显著（p<0.05）,而30%和40%乙醇作用维持时间较长且效果显著（p<0.05）。      

Effect of heat treatment and individual shrink packaging on quality and nutritional value of bell pepper stored at suboptimal temperature

The goal of this study was to develop a technology for prolonged storage of pepper fruit at low temperature, based on physical treatments and packaging materials. Physical and compositional changes of red bell pepper fruit (Capsicum annuum L. cv.’Selika’) were monitored during 21 days of cold storage (at 2 °C) plus 3 days at 20 °C (market simulation). Fruits were treated with tap and hot water and stored without packaging or sealing each fruit in individual shrink packaging (Cryovac®). This research revealed that individual shrink packaging following prestorage with hot water rinse (55 °C for 15 s) over brushes, significantly reduced weight loss, softening, decay incidence and chilling injury, while maintaining a quality. The wrapped fruit ripened normally (carotenoid content increased) during shelf‐life period, when shifted to 20 °C after unwrapping. This study showed that antioxidant levels of pepper fruit may be preserved during storage.     

真空充氮热处理对鲜切双孢蘑菇自由基和保护酶的影响

为延缓鲜切双孢蘑菇的衰老进程,延长保鲜期,研究了不同真空度（0、-20、-40、-60、-80、-98 k Pa）下充氮热处理对鲜切双孢蘑菇贮藏中的超氧阴离子产生速率、过氧化氢（H2O2）含量、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性、抗坏血酸过氧化物酶（APX）活性和抗坏血酸（As A）含量的影响。结果表明,在较低真空度（-20^-60 k Pa）,尤其是-40 k Pa充氮热处理可显著（p<0.05）提高SOD和CAT活性,降低了鲜切双孢蘑菇超氧阴离子产生速率,减少了H2O2的积累;高真空度（-98 k Pa）充氮热处理可显著提高鲜切双孢蘑菇As A含量;真空充氮热处理可抑制鲜切双孢蘑菇贮藏中APX活性的升高。      

Response surface optimisation of germination conditions to improve the accumulation of bioactive compounds and the antioxidant activity in quinoa

Germination has been proposed as an economic approach to improve the content of bioactive compounds in pseudocereals. In this work, response surface methodology (RSM) was employed to investigate the impact of germination conditions on the phytochemical content and antioxidant activity of quinoa. The use of desirability methodology showed that the optimum conditions to maximise the content of total phenolic content (TPC) and antioxidant activity in sprouted quinoa were 20 °C for 42 h. Sprouts produced under these conditions exhibited increases of 80% and 30% in TPC and antioxidant activity, respectively, compared to un‐germinated seeds, and contained high γ‐aminobutyric acid (GABA) concentration. The nonsignificant lack‐of‐fit and high determination coefficients obtained confirmed the suitability of the predictive models developed for TPC and antioxidant activity, whilst the one obtained for GABA was not significant (R² < 0.75) within the conditions studied. Sprouting under optimum conditions enhanced the content of both flavonoid and nonflavonoid compounds, being the increase in flavonoids more pronounced. Kaempferol‐O‐dirhamnosyl‐galactopyranose and quercetin‐O‐glucuronide were the compounds that experienced the most noticeable increase in quinoa after germination. In conclusion, this study provides useful information on the optimum germination conditions to improve the levels of health‐promoting compounds in quinoa.     

Quantitative bioactive compounds assessment and their relative contribution to the antioxidant capacity of commercial orange juices

Dietary recommendations for healthy eating include the consumption of fruit juices whose health effects are ascribed, in part, to carotenoids, phenolic compounds and vitamin C. These bioactive compounds have been implicated in the reduction of degenerative human diseases, mainly due to their antioxidant potential. Orange juice is characterized by substantial accumulation (apart from ascorbic acid) of flavonoids and carotenoids. Commercial orange juice is the main human dietary source of antioxidant compounds in developed countries. The qualitative and quantitative determination of carotenoid, flavonoid and vitamin C content of Spanish commercial orange juices was achieved by high‐performance liquid chromatography. The health‐related properties of bioactive compounds contained in orange juice are based on their antioxidant activity. The antioxidant capacity of these juices was assessed by 2,2‐diphenyl‐1‐picrylhydrazyl stable radical scavenging and was compared with a freshly squeezed orange juice. In addition, the relative contribution of the different bioactive compounds to the antioxidant activity of orange juices was calculated. Total vitamin C was found to be the major contributor to the antioxidant potential of the orange juices studied, followed by flavonoid and carotenoid compounds. Ascorbic acid, total vitamin C and β‐cryptoxanthin content correlated positively with the free‐radical scavenging parameters. No significant differences, in terms of antioxidant capacity, were found between commercial traditional pasteurized orange juices and freshly squeezed orange juice. Copyright © 2003 Society of Chemical Industry     

Effect of light,food additives and heat on the stability of sorghum 3-deoxyanthocyanins in model beverages

This work aimed to evaluate the stability of sorghum 3-deoxyanthocyanins (DXA) in model beverages (pH 3.5) elaborated with crude sorghum phenolic extract, containing ascorbic acid and sulphite, under fluorescent light exposure and subjected to heat treatment. There was no significant difference in the DXA degradation during storage under light exposure (24.16%) and absence of light (20.72%). DXA degradation did not differ in the presence of ascorbic acid during storage under light exposure (23.99–25.38%) and absence of light (19.87–21.74%). The addition of sulphite caused an initial bleaching reaction, but as a reversible reaction, the anthocyanin content was higher on the last day of storage compared to the first day. There were no significant differences in total anthocyanin content of all treatments subjected to the heat treatment (80 °C for 5 and 25 min). Thus, crude DXA are very stable under light, additives and heat, and may be useful as natural food colourants.     

Effect of relative humidity and storage time on the bioactive compounds and functional properties of grapefruit powder

The modified state diagram of freeze-dried grapefruit powder was obtained in order to determine the critical water content and critical water activity that cause the glass transition of the amorphous matrix at storage temperature. At 20 °C these values were in the ranges of 0.031–0.057 g water/g product and 0.089–0.210, respectively. Below those critical values, the glassy state of the amorphous matrix is guaranteed, thus avoiding an increase in the rate of the deteriorative reactions related to the loss of the bioactive compounds in the fruit (organic acids, vitamin C, main flavonoids, and total phenols) which contribute to the antioxidant capacity (AAO) of grapefruit. In the rubbery state, a certain time is needed for these degradative reactions to start. This time depends on the water content of the sample, the greater the water content the lower the time needed. In this study, the powder was stable for a relatively long storage time (3 months) regardless the relative humidity, due to the limited mobility of the molecular system. Between 3 and 6 months had to pass before a significant loss of bioactive compounds was observed; the higher the relative humidity, the greater the loss.     

青菜热水浴处理保绿机理研究

通过对热处理后青菜组织内部叶绿素-蛋白质牢固性、叶 绿素降解产物和过氧化物酶活性变化的检测,初步考察 了青菜热水浴处理的保绿机理。结果表明,叶绿素的降解 速率与叶绿素-蛋白质结合牢固性之间无显著相关性:热 处理抑制了脱镁叶绿素氧化酶的活性,使叶绿素降解中 间产物造成积累,进而对叶绿素酶和脱镁叶绿素螯合酶 形成反馈抑制,从而延缓了青菜叶片的黄化;热处理抑制 了过氧化物酶的活性,从而阻止了由过氧化物酶引起的 过氧化反应对叶绿体的伤害,减缓了叶绿素的降解。热水 浴处理影响了青菜蛋白质的合成,产生了热激蛋白 (HSPs)。