Changes in hydrophilic and lipophilic antioxidant activity and related bioactive compounds during postharvest storage of yellow and purple plum cultivars

Eight plum cultivars (four dark-purple and four yellow) were harvested at the commercial ripening stage, and changes of fruit quality properties were evaluated during cold storage and subsequent shelf-life, with special emphasis on bioactive compounds (phenolics, anthocyanins and carotenoids) and antioxidant activity (TAA). From the eight plum cultivars, four showed the typical climacteric ripening pattern (‘Blackamber’, ‘Larry Ann’, ‘Golden Globe’ and ‘Songold’) while four behaved as suppressed-climacteric types (‘Golden Japan’ ‘Angeleno’, Black Diamond’ and ‘TC Sun’), the latter being described for the first time. At harvest, large variations in phytochemicals and antioxidant activity were found among cultivars in peel and pulp tissues, although phytochemical concentration and antioxidant activity were higher in the peel than in the flesh (2–40-fold depending on the bioactive compound). During storage, increases in total phenolics for all cultivars (peel and pulp), in total anthocyanin content in the peel of the dark-purple plums, and total carotenoids in the peel and pulp of the yellow cultivars were observed. This behaviour of the bioactive compounds was reflected in TAA changes, since hydrophilic-TAA (H-TAA) was correlated with both phenolics and anthocyanins, while lipophilic-TAA (L-TAA) was correlated with carotenoids. L-TAA comprised about 30–50% of the TAA in plum tissues. Carotenoids and phenolics (and among them the anthocyanins) could be the main lipophilic and hydrophilic compounds contributing to L-TAA and H-TAA, respectively. No significant loss of bioactive compounds and TAA occurred during prolonged plum storage. Moreover, for a better evaluation of the antioxidant potential of plums, the contribution to carotenoids should not be overlooked.     

二月兰花瓣花色苷组成分析

为了研究二月兰花色苷成分组成特点,本试验以3份二月兰为试材,利用特征颜色反应确定二月兰花瓣的色素类型,并通过高效液相色谱-质谱联用技术(HPLC-Q-TOF-MS)分析花色苷种类及其含量。研究结果表明,3份二月兰花瓣中均不含类胡萝卜素,除白色花瓣以外,其余均含花色苷。蓝紫色花瓣的花色苷含量最高,粉色次之。在二月兰花瓣中共检测到了7种花色苷成分,通过与已有文献比对,推定其成分为矢车菊素3-芸香糖苷、锦葵素3,5-二葡萄糖苷、矢车菊素3-香豆酰葡萄糖苷-5-葡萄糖苷、矢车菊素3-p-香豆酰二葡萄糖苷-5-葡萄糖苷、矢车菊素3-阿魏酰槐糖苷-5-丙二酰葡萄糖苷、矢车菊素3-香豆酰槐糖苷-5-丙二酰葡萄糖苷、矢车菊素3-(6′-丙二酰葡糖苷-2′-(6′′-香豆酰-2′′-羟基苯甲酰葡糖苷))-5-丙二酰葡糖苷。粉色花瓣中仅含矢车菊素的花色苷衍生物,而蓝紫色花瓣中则含矢车菊素和锦葵素的花色苷衍生物。本研究为二月兰花色苷成分的进一步分离和鉴定工作提供了参考,同时也为二月兰花色的分子育种提供理论依据。     

Biofortification of taro (Colocasia esculenta) through breeding for increased contents in carotenoids and anthocyanins

Biofortification of taro (Colocasia esculenta) has never been studied. The aim of the present study is to compare the chemical compositions and individual constituent contents for major compounds (starch, sugars, cellulose, proteins, minerals), carotenoids and anthocyanins between parents and hybrids selected first for their agronomic performance and second for their corm characteristics (flesh color, quality and taste). For major compounds, 45 selected hybrids were compared to 66 cultivars and for carotenoids and anthocyanins, 34 selected hybrids were compared to 79 cultivars. Total sugars, cellulose and mineral contents presented moderate increases in hybrids. Carotenoids and anthocyanins contents were not correlated with corm flesh colors, most likely in relation with the wide range of the observed variability. Anthocyanin contents could not be increased in the selected hybrids, while total carotenoid contents were increased by more than fourfolds. The results of this study indicate that carotenoid contents can be rapidly improved by selecting plants of good agronomic performance and corm shape with increased density of yellow and orange colors. Potential applications to taro breeding programs are discussed.     

Changes in bioactive compounds and response to postharvest storage conditions in purple eggplants as affected by fruit developmental stage

Fruit maturity stage at harvest influences the response to postharvest storage conditions and bioactive compounds content. In this work fruit from two purple eggplant cultivars (Monarca and Perla Negra) were harvested at 12, 15, 18, 20 and 23 d after fruit set (designated as stages I through V) and changes in size, dry weight, calyx area, cell wall material (AIR, alcohol insoluble residue), firmness, respiration, and antioxidants (peel anthocyanins and pulp carotenoids, ascorbic acid, phenolics and chlorogenic acid) were determined. In a second set of experiments the postharvest performance of fruit harvested at stages I (“baby” eggplants), III and IV (traditional harvest stages) during storage at 0 or 10 °C was assessed. Fruit growth continued until late ripening in contrast to calyx expansion and peel anthocyanin accumulation, which were relatively earlier events. Fruit dry weight decreased between stages I and III, remaining constant afterwards. “Baby” eggplants had higher antioxidant capacity, chlorogenic acid (ChA), carotenoids and ascorbic acid contents than late-harvested fruit. ChA predominated in pulp placental tissues at stage I, spreading throughout the fruit core at as ripening progressed. No marked differences in dry mass, antioxidant capacity or responses to postharvest storage regimes were found between fruit harvested at stages III and IV. Late pickings increased yields and led to less dense fruit, which had lower respiration rates. Within this harvest window, storage at 10 °C maximized quality maintenance. In contrast “baby” eggplants stored better at 0 °C. Understanding the developmental changes in bioactive compounds and postharvest performance may help in the maximization of fruit antioxidant properties as well as in the selection of the optimal handling conditions for each ontogenic stage.     

Colour development and quality of mangosteen (Garcinia mangostana L.) fruit during ripening and after harvest

The colour of mangosteen (Garcinia mangostana L.) fruit changes from green to purple black after harvest as the fruit ripens, and is used as a quality guide for growers and consumers. We determined the relationship between anthocyanin composition and content during fruit colour development in relation to fruit maturity and postharvest quality. Fruit at different stages of maturity (light greenish yellow with 5% scattered pink spots to purple black) were harvested and kept at 25 °C (85–90% RH). Fruit from each maturity stage all developed to the final purple black stage. During the postharvest period, hue angle values and pericarp firmness decreased significantly, while soluble solids contents increased. Anthocyanin contents in the outer pericarp were higher than in the inner pericarp and increased to a maximum at the final colour stage. Sensory evaluation and fruit quality (hue angle values, soluble solids and titratable acidity) of fruit harvested at the different stages did not differ once the fruit had finally developed to the purple black stage. The anthocyanins in the outer pericarp mainly consisted of five compounds, identified by HPLC/MS as cyanidin-sophoroside, cyanidin-glucoside, cyanidin-glucoside-pentoside, cyanidin-glucoside-X, cyanidin-X₂ and cyanidin-X, where X denotes an unidentified residue of m/z 190, a mass which does not correspond to any common sugar residue. Cyanidin-3-sophoroside and cyanidin-3-glucoside were the major compounds and the only ones that increased with fruit colour development.     

不同基因型玉米籽粒类胡萝卜素与花色苷色素积累规律

以黄色(特爆2号)、红色(西星赤糯1号)、紫色(紫糯香)和黑色(西星黑糯1号) 4种颜色的玉米为材料,通过徒手切片以及分光光度法,研究了玉米籽粒色素的组成、分布和积累规律。结果显示,西星赤糯1号玉米籽粒色素主要由花色苷和类胡萝卜素构成,花色苷主要存在于果种皮中,类胡萝卜素主要存在于胚与胚乳中;特爆2号玉米籽粒色素主要由类胡萝卜素构成,分布于胚与胚乳中;紫糯香及西星黑糯1号玉米籽粒色素主要由花色苷构成,主要存在于糊粉层中。除西星赤糯1号的花色苷积累首先出现于胚上方的花柱遗迹附近外,其余品种色素均首先在籽粒顶端出现,随后向四周延伸。玉米籽粒色素(除紫糯香)吸收峰随时间的变化先升高后降低。灌浆前期玉米果穗色素含量上部>中部 >下部,到灌浆后期,中部色素含量大于其他两部分色素含量。     

‘皮球桃’及其突变体类胡萝卜素积累及相关关键基因分析

本研究以‘皮球桃’及其芽变桃不同发育阶段的果肉与叶片中脉为试材,采用HPLC法测定两种桃中类胡萝卜素的组分构成与含量积累,并对类胡萝卜素生物合成及代谢过程中关键基因的转录水平进行实时荧光定量PCR分析。结果显示,芽变桃中类胡萝卜素总含量极显著高于‘皮球桃’,β-隐黄质、α-胡萝卜素和β-胡萝卜素的积累差异是造成两种桃呈色不同的主要原因。实时荧光定量PCR结果表明,CCD4在果肉和叶片中脉中的表达规律完全相同,且与类胡萝卜素的积累模式一致,因此CCD4的表达差异可能是导致芽变桃果肉及叶片中脉突变为黄色的重要原因。本研究利用‘皮球桃’及其自然突变体作为探讨类胡萝卜素合成及代谢调控的理想材料,以期从生理及分子层面揭示变异黄桃的形成机理,为桃的类胡萝卜素调控基因开发、变异的早期鉴定、认识和选育富含类胡萝卜素桃品种提供理论基础。     

丰水梨果实采后生理生化变化的研究

研究了20℃、相对湿度80％～85％条件下丰水梨果实采后软化与褐变的生理生化变化规律。结果表明,丰水梨具有呼吸和乙烯跃变期,跃变期过后果肉硬度下降幅度较小．但果实风味急剧下降。跃变前期果肉快速软化是由乙烯和淀粉酶共同参与,之后果肉软化是由PG和纤维素酶共同作用的结果。果实不同部位褐变度、酚类物质、类黄酮及丙二醛含量均为果皮〉果心〉果肉．PPO活性依次为果心〉果皮〉果肉,果皮相对电导率低于果肉和果心。影响丰水梨贮藏品质的关键因素是果肉软化和风味劣变．而不是褐变。     

套袋对山葡萄花色苷及相关品质的影响

为了研究套袋对山葡萄果实可溶性固形物、可滴定酸、还原糖和总花色苷含量的影响,为生产优质山葡萄提供理论指导。以‘双红’山葡萄为试验材料,应用HPLC技术,研究套袋对山葡萄花色苷及相关品质的影响。结果表明,套袋可使果实的滴定酸含量显著增加,可溶性固形物和含糖量降低,总花色苷含量无显著差异,花青素-3-葡萄糖苷含量显著低于对照组。在采收期提前解袋可使还原糖增加,总花色苷含量无显著差异,花青素-3-葡萄糖苷含量增加显著。     

Stability of flower colors due to anthocyanin-flavone copigmentation in Japanese garden iris, Iris ensata Thunb.

The fading of flower color in bluish purple and reddish purple cultivars of Iris ensata and the in vitro stability of malvidin 3RGac5Gand petunidin 3RGac5G due to copigmentation with isovetixin under different pH conditions were examined. The bluish purple cultivars exhibited higher flower color stability than the reddish purple cultivars 2 days after anthesis. In the absence of isovitexin, malvidin 3RGac5G and petunidin 3RGac5G were not able to maintain color stability except at low pH. However, the color stability of malvidin 3RGac5G and petunidin 3RGac5G was increased by copigmentation with isovitexin under all pH conditions tested. Most remarkable was the stabilization of both anthocyanins due to the copigmentation at pH 4.2–6.2. Therefore, it can be concluded that the stability of flower color in the bluish purple cultivars of malvidin 3RGac5Gand petunidin 3RGac5G type of I. ensata is caused at least in part by the copigmentation between these anthocyanins and isovitexin. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thin-layer chromatographic analysis of flower color phenotypes in Dendranthema grandiflorum Ramatuelle inbreds and clonal cultivars

Summary Four glasshouse and 13 garden chrysanthemum cultivars or inbred seedlings from the color groups white, yellow, pink/purple, and orange/red/bronze were analyzed with thin-layer chromatography (TLC) for qualitative and quantitative pigment constituents. TLC confirmed the presence of eight carotenoids in yellow and bronze cultivars. Qualitative differences exised only for spots 5–8. Rf values for lutein matched those of spot 4. Flavonoid analysis of purples and bronzes revealed two anthocyanidins, one of which was cyanidin, one flavone, and two phenylpropanoids. White cultivars had four phenylpropanoids, two of which were caffeic and ferulic acids. In most cases, inbred and non-inbred cultivars within a given phenotypic class did not exhibit qualitative differences. Color analysis could be pursued at any level of inbreeding, but inheritance studies would be severely hampered using non-inbred genotypes of this hexaploid floricultural crop.     

Changes in antioxidant activity and postharvest quality of sweet pomegranates cv. Hicrannar under modified atmosphere packaging

The effects of different modified atmosphere packaging (MAP) on antioxidant compounds and storage quality of ‘Hicrannar’ sweet pomegranates were investigated during long term storage. Pomegranates were harvested at the commercial harvest stage and packed in two different types of MAP (MAP1 and MAP2). After packaging, all fruit were stored at 6 °C and 90–95% RH for 120 days, then removed from storage for different quality analyses. Some fruit were kept at 20 °C for 3 days to simulate a period of shelf-life. Fruit weight loss, decay index, skin color, total titratable acidity, total soluble solids content, total phenolics, total anthocyanins and antioxidant activity were determined. Internal atmospheres created by the MAP were periodically assessed during cold storage, and CO₂ concentrations increased and O₂ concentrations decreased inside the MAP. MAP significantly reduced weight loss after both 120 days of cold storage and shelf-life. MAP2 was the most effective packaging in reducing weight loss. Storage of pomegranates in MAP also reduced decay and the decay index, and maintained visual appearance compared to control fruit. During storage, a decrease in L* and C* values and an increase in h° values were observed in all treatments. However, fruit stored in MAP2 had higher L*, C* and lower h° values than in other treatments. Titratable acidity and total soluble solids decreased after cold storage and shelf-life, and no significant differences among treatments were found. Total phenolics, total anthocyanin contents and antioxidant activity increased during the storage period in control fruit.     

黄冠梨果皮褐斑病与酚类物质代谢的关系

对套袋黄冠梨果皮褐斑病果酚类物质以及相关氧化酶活性进行了分析。结果表明,与正常果实比较,褐斑严重的果皮和果肉中酚含量、POD和PPO活性较高,但SOD活性差异不显著;同时,果皮褐斑区域较正常区域酚含量、POD、PPO和SOD活性较高。正常果实表面喷洒1％CaCl2、0．1mmol／L CPZ、0．1mmol／L TFP、0．5mmol／L SO和0．05mmol／L EB溶液后,均未对果皮酚类物质含量产生明显影响,仅EB诱发褐变,而CaCl2降低了PPO活性,SO、EB和TFP的作用相反,CPZ的作用较小。这说明,果皮发生褐变与PPO活性显著升高有密切关系,Ca^2＋-CaM系统和Ca^2＋-ATPase参与了褐变过程。     

盐胁迫对油桃生理生化特性的影响

为分析不同油桃的耐盐特性,为后续的耐盐品种选育研究打下基础,以‘华光’油桃盆栽苗为试材,研究不同程度盐胁迫对植株茎生理指标的影响。试验发现0.4%盐胁迫下各指标与对照组无明显差异,0.8%盐胁迫中后期开始有一定影响,而1.2%盐胁迫初期时相关指标便有极明显差异,表明该盐环境为植株能够承受的极限。在此基础上,以‘中油桃4 号’、‘艳光’、‘华光’、‘千年红’、‘玫瑰红’5 个品种油桃盆栽苗为试验材料,分析了1.2%盐溶液胁迫下的生理指标变化,研究不同品种油桃的耐盐特性。结果表明：不同油桃品种在盐胁迫下的表现差异性很大,黄肉品种‘中油桃4 号’耐盐特性优于‘千年红’;白肉品种‘华光’耐盐性强于‘艳光’,‘玫瑰红’高于‘华光’;白肉品种耐盐特性整体上强于黄肉品种。     

‘赤霞珠’和‘梅露辄’不同营养系果实不同部位酚类物质含量的比较分析

为有效发挥酿酒优良品种‘赤霞珠’和‘梅露辄’不同营养系的优点,为选育果实中酚类物质含量较高的营养系提供依据,分别以‘赤霞珠’和‘梅露辄’葡萄品种的4个营养系成熟果实为材料,取样测定其单粒重、可溶性固形物、可滴定酸含量,示差比色法测定果皮中的总花色苷含量,比色法测定果皮、果肉和种子中的总酚、单宁、总类黄酮和原花色素含量。结果表明,‘赤霞珠’和‘梅露辄’各营养系浆果单粒重无显著差异;‘赤霞珠’4个营养系中,‘赤霞珠170’和‘赤霞珠338’的可溶性固形物含量分别为最高和最低,‘赤霞珠338’和‘赤霞珠685’的可滴定酸含量分别为最高和最低;‘梅露辄’4个营养系中,可滴定酸含量最低的是‘梅露辄181’,最高的是‘梅露辄346’。各营养系果粒果皮、果肉和种子中各酚类含量具有明显差异;‘赤霞珠338’果皮总酚、单宁、总类黄酮和原花色素含量均最高,而种子中各含量均最高的是‘赤霞珠169’;‘梅露辄’4个营养系中,‘梅鹿辄348’果皮总酚、单宁和花色苷含量最高,而种子中含量最高的是‘梅露辄181’。‘赤霞珠’和‘梅鹿辄’果实品质存在品种差异,各营养系间也存在差异,酚类物质含量以果皮中较高,果肉中最低。‘赤霞珠338’果皮和‘赤霞珠169’种子中总酚、单宁、总类黄酮和原花色素含量均最高,而‘梅鹿辄348’果皮中总酚、单宁和花色苷含量最高,‘梅鹿辄181’种子中总酚和单宁含量最高。     

Relationship between browning and related enzymes (PAL, PPO and POD) in rambutan fruit (Nephelium lappaceum Linn.) cvs. Rongrien and See-Chompoo

Rambutan (Nephelium lappaceum Linn.) fruit cvs. Rongrien and See-Chompoo were stored in low (60–70%) and high (85–95%) relative humidity (RH) environments at 25 °C for 6 d. Changes in weight loss, browning index, phenols content and activities of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) were measured. By d 6 of storage, browning was severe in the spinterns but slight in the peel of both cultivars. High RH delayed spintern browning but had only a small effect on peel browning. The phenols content and PAL activity in peel from both cultivars were generally higher than in the spinterns. RH had no effect on the changes in phenols during storage but PAL activity increased in the peel but not spinterns of both cultivars at d 4 of storage in low RH. The initial activities of PPO and POD in spinterns of both cultivars were higher than in peel. PPO activity in the spinterns of both cultivars was similar and was not affected by RH. The initial activity of POD was lower in the peel and the spinterns of Rongrien fruit but there were no clear responses to RH during storage. Higher activities of PPO and POD in the spinterns compared to the peel may also be a factor in the higher rates of browning of the spinterns.     

1-MCP extends the storage and shelf life of mangosteen (Garcinia mangostana L.) fruit

Mangosteen (Garcinia mangostana L.) fruit were harvested when the peel (pericarp) was light greenish yellow with scattered pinkish spots. Fruit were exposed to 1 μL L⁻¹ 1-methylcyclopropene (1-MCP) for 6 h at 25 °C and were then stored at 25 °C (control) or 15 °C. The 1-MCP treatment only temporarily delayed softening of the fruit flesh, during storage. Storage life, defined as the time until the pericarp was dark purple, was much longer in fruit stored at 15 °C than in fruit stored at 25 °C. It was also longer in 1-MCP treated fruit (storage life at 15 °C: control 18 d, 1-MCP-treated fruit 27 d). The 1-MCP treatment also increased the length of shelf life, defined as the time until the pericarp turned blackish purple or showed calyx wilting, at 25 °C. 1-MCP treatment reduced ethylene production. It also reduced pericarp levels of 1-aminocyclopropane-1-carboxylic acid (ACC), and the pericarp activities of ACC synthase (ACS) and ACC oxidase (ACO). In the fruit flesh, in contrast, 1-MCP did not affect ACC levels and ACS activity, but the treatment reduced ACO activity. Taken together, both the storage life and the shelf life of the fruit were extended by the 1-MCP treatment. A decrease in ACO activity largely accounted for the effects of the 1-MCP on ethylene production in the pericarp.     

不同果皮颜色酿酒葡萄品种果实不同部位酚类物质含量比较及抗氧化能力分析

为筛选出酚类物质含量高且具有较高抗氧化活性的酿酒葡萄种质资源,分别以4个红色和4个白色酿酒葡萄成熟果实为材料,比色法测定果皮、果肉和种子中的总酚、单宁、总类黄酮、原花色素和黄烷醇含量,以总还原力、DPPH自由基、ABTS⁺·自由基清除能力评价其抗氧化能力。结果表明,各品种果皮、果肉和种子中各酚类物质含量具有明显差异,但均以果肉中含量最低。红色品种果皮和种子中酚类物质含量均高于白色品种（‘小白玫瑰455’除外）,其中以‘黑比诺667’中总酚、单宁和总类黄酮含量最高,而果皮原花色素和黄烷醇含量以‘蛇龙珠’最高,种子原花色素含量以‘法国蓝’最高。白色品种中,‘小芒森’果皮各酚类物质含量均最低,而种子中含量以‘小白玫瑰455’最高。各葡萄品种果皮和种子的抗氧化能力和其总酚、单宁、总类黄酮、原花色素和黄烷醇含量之间均为显著正相关,相关系数在0.8383~0.9983,而果肉中的相关性较弱。选用的3种方法对葡萄果实抗氧化活性进行评价时,测定结果在不同方法间存在协同性与差异性。     

Preharvest application of abscisic acid promotes anthocyanins accumulation in pericarp of litchi fruit without adversely affecting postharvest quality

Pericarp colour of litchi fruit is an important quality attribute that determines its market value and consumer acceptance. Plant growth regulators (PGR) such as abscisic acid (ABA) and ethephon are known to play important roles in peel colour development during maturation and ripening of non-climacteric fruits (e.g. grape and litchi). Our aim was to investigate the effects of preharvest application of ABA, ethephon and their combination on pericarp colour and fruit quality of litchi (cv. Calcuttia) and also to assess the potential effects on postharvest performance of fruit. Exogenous application of ABA (150 or 300 mg L⁻¹) at the colour-break stage significantly increased the concentration of total anthocyanins and cyanidin-3-O-rutinoside, the major anthocyanin contributing ∼71–96% of the total anthocyanins, in litchi pericarp compared to ethephon (500 μL L⁻¹). Among different anthocyanins quantified, the relative contribution of cyanidin-3,5-diglucoside to the total anthocyanins was significantly higher in all PGR-treated fruit compared to the control, but the concentration of cyanidin-3-O-glucoside was specifically enhanced by ABA. No significant effect on the concentrations of epicatechin, and quercetin-3-O-rutinoside was observed in response to PGR treatments. Ethephon (500 μL L⁻¹) treatment did not significantly increase the anthocyanin levels in pericarp, but it caused more degradation of chlorophyll pigments than control. Aril quality with regard to firmness, soluble solids and acidity was not significantly affected by PGR treatments, except that ethephon-treated fruit showed significant softening and lower acidity. Postharvest changes in fruit quality attributes including pericarp browning during cold storage at 5 °C for 14 d were mainly related to the storage duration effect, rather than PGR treatment. In conclusion, ABA treatment (150 or 300 mg L⁻¹) at the colour-break stage enhanced anthocyanins accumulation in litchi pericarp without adversely affecting postharvest quality and storage stability for 14 d.