Storage effects on anthocyanins, phenolics and antioxidant activity of thermally processed conventional and organic blueberries

BACKGROUND: Consumer demand for products rich in phytochemicals is increasing as a result of greater awareness of their potential health benefits. However, processed products are stored for long‐term and the phytochemicals are susceptible to degradation during storage. The objective of this study was to assess the storage effects on phytochemicals in thermally processed blueberries. Thermally processed canned berries and juice/puree were analysed for phytochemicals during their long‐term storage. RESULTS: The phytochemical retention of thermally processed blueberries during storage was not influenced by production system (conventional versus organic). During 13 months of storage, total anthocyanins, total phenolics and total antioxidant activity in canned blueberry solids decreased by up to 86, 69 and 52% respectively. In canned blueberry syrup, total anthocyanins and total antioxidant activity decreased by up to 68 and 15% respectively, while total phenolic content increased by up to 117%. Similar trends in phytochemical content were observed in juice/puree stored for 4 months. The extent of changes in phytochemicals of thermally processed blueberries during storage was significantly influenced by blanching. CONCLUSION: Long‐term storage of thermally processed blueberries had varying degrees of influence on degradation of total anthocyanins, total phenolics and total antioxidant activity. Blanching before thermal processing helped to preserve the phytochemicals during storage of blueberries. Copyright © 2011 Society of Chemical Industry     

Comparison of anthocyanins and phenolics in organically and conventionally grown blueberries in selected cultivars

Consumption of berries has become popular among health-conscious consumers due to the high levels of valuable antioxidants, such as anthocyanins, and phenolic compounds in berries. Four Rabbiteye blueberry cultivars (i.e., Powderblue, Climax, Tifblue, and Woodward) grown organically and conventionally were compared regarding their chemical profiles and antioxidant capacity in terms of total phenolic content (TPC), total anthocyanin content (TAC) and ORAC activity. Regardless of the high TPC, TAC and ORAC in both organically and conventionally grown blueberries, not all the organic berries showed significantly higher TPC, TAC and ORAC than the conventional berries. The chemical profiles (i.e., the free phenolic compounds and anthocyanins) were determined with aid of HPLC-MS, by which 13 individual anthocyanins and seven free phenolics were identified. This study demonstrated the subtle differences of bioactive phytochemicals between the organically and conventionally grown berries.     

Strawberries from integrated pest management and organic farming: Phenolic composition and antioxidant properties

Consumer awareness, pesticide and fertilizer contaminations and environmental concerns have resulted in significant demand for organically grown farm produce. Consumption of berries has become popular among health-conscious consumers due to the high levels of valuable antioxidants, such as anthocyanins and other phenolic compounds. The present study evaluated the influence that organic farming (OF) and integrated pest management (IPM) practise exert on the total phenolic content in 22 strawberry samples from four varieties. Postharvest performance of OF and IPM strawberries grown in the same area in the centre of Portugal and harvested at the same maturity stage were compared. Chemical profiles (phenolic compounds) were determined with the aid of HPLC-DAD/MS. Total phenolic content was higher for OF strawberry extracts. This study showed that the main differences in bioactive phytochemicals between organically and IPM grown strawberries concerned their anthocyanin levels. Organically grown strawberries were significantly higher in antioxidant activity than were the IPM strawberries, as measured by DPPH and FRAP assays.     

Comparative study of phenolic content and antioxidant activity of strawberry puree,clear, and cloudy juices

The aim of this study was to determine the concentrations of phenolic compounds and their antioxidant activity in different kinds of juice: clear, cloudy, and puree which were made from three different strawberry cultivars (Elkat, Kent, and Senga Sengana). The anthocyanins, p-coumaric acid, ellagic acid, quercetin, keampferol derivatives, (+)-catechin, proanthocyanidins content and degree of proanthocyanidin polymerization, were determined both in the fresh and after 6 months of storage at 4 and 30 °C. Freshly produced juices contained higher amounts of phenolics, especially of anthocyanins and proanthocyanidins, than those stored for 6 months at 4 and 30 °C. The processing of the clear juice showed the higher loss of all phenolic compounds. The antioxidant capacity was the smallest for clear, and the highest for the puree juices. This was assessed by measurements made with different antioxidant activity assays: ABTS and FRAP. The puree of strawberry juice had significantly higher levels of the phenolic compounds and showed more antioxidant activity than the clear and cloudy juices, before and after storage in all strawberry cultivars.     

Effects of Food Processing on Blueberry Antiproliferation and Antioxidant Activity

Cultivated highbush (Vaccinium corymbosum L.) and wild lowbush (Vaccinium angustifolium Ait.) blueberries are excellent sources of phytochemicals that are believed to have significant biological activity. The objective of this study was to determine whether incorporation of blueberries into food products affects their phenolic content or antioxidant and antiproliferation activity. Several blueberry fruit‐containing products including fresh, individually quick frozen (IQF), freeze‐dried, spray‐dried, heat‐dried, cooked, juice concentrate, pie filling, and jam were fractionated to remove sugars and isolate groups of phytochemicals based on solubility. The fractions were analyzed for total phenolics and assayed for ferric reducing antioxidant power (FRAP) antioxidant activity, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity, and hepa‐1c1c7 antiproliferative activities. For both cultivated and wild berries, fresh and IQF berries had the highest total phenols, antioxidant activity, and antiproliferation activity. Whole freeze‐dried wild blueberries also retained significant antiproliferative activity in 2 fractions eluted with acetone (fraction 4, 4% of control cell growth at 20 (μg/mL) and 50% aqueous acetone (fraction 5, 69% of control cell growth at 20 (μg/mL) and ranked close to the activities recorded for fresh (30% of control cell growth at 20 (μg/mL for fraction 5) and IQF whole fruit (27% of control cell growth at 20 (μg/mL for fraction 5). Products that were heat‐processed retained most of the antioxidant activity and total phenolics found in unprocessed whole fruit. However, the heat‐treated products lacked or had diminished antiproliferation activity, suggesting that although products may be high in phenolic compounds and antioxidant activity, some forms of bioactivity may be compromised by harsh processing methods.     

Partial Least Squares Analysis of the Relationship Between Chemical Composition and Phenolic Compounds in Blueberry Cultivars

Blueberries (Vaccinium spp.), one of the most widely consumed fruits worldwide, are rich in nutrients and exhibit antioxidant activity. In this study, the partial least squares and principal component analyses were used and the chemical composition and mineral and phenolic compound contents of blueberry cultivars suited to northern China were determined. Blueberries growing in northern China contain a rich variety of biologically active compounds at high concentrations and have high nutritive mineral values. In general, the chemical composition data of the blueberry cultivars examined were similar to those obtained by the US Department of Agriculture (USDA). However, the mineral content data showed iron and potassium concentrations that were slightly higher than those found by the USDA. In addition, the iron concentrations were lower than those found in the literature for Brazilian cultivars. The zinc, magnesium, and vitamin C in blueberries may promote the growth and accumulation of total phenols and anthocyanins, while total acid, iron, and potassium have opposite effects. Total phenols correlated positively with anthocyanins. Differences in protein, total carbohydrate, potassium, and sodium between cultivars could affect total phenol and anthocyanin contents. Adjusting the total acid concentration and reducing the sugar and mineral contents may affect anthocyanin content in blueberries. These changes may improve the nutritional value and fruit quality of blueberries.     

Antioxidant activity,anthocyanins, and phenolics of rabbiteye blueberry (Vaccinium ashei) fluid products as affected by fermentation

Frozen rabbiteye blueberries (Vaccinium ashei) were processed into juice (BJ), wines made without (BW1) or with (BW2) skin contact fermentation, and vinegars made from BW1 (JV), BW2 (WV) or blueberries (BV). Total phenolics, total anthocyanins, antioxidant activities (beta-carotene bleaching assay and ferric thiocyanate assay), and antiradical activity (DPPH radical-scavenging method) of these fluid products were determined. The differences in total anthocyanin contents of all blueberry products were significant. The BW2 had the highest content of anthocyanins and polyphenols and the highest beta-carotene bleaching activity and antiradical activity. Acetification decreased total anthocyanin content, total polyphenols and antioxidant activities. Correlations indicate that anthocyanins made significant contributions than did phenolics to antioxidant activities of products. The abilities of BJ, BW1 (wine from blueberry juice), and BW2 to inhibit linoleic acid peroxidation were high (∼95%). The abilities of vinegar products to inhibit linoleic acid peroxidation were low. The results indicate that skin-contact fermentation is a better method for obtaining higher antioxidant activity of blueberry products. Also, acetification significantly decreased anthocyanins and antioxidant activities.     

Frozen Wild Blueberry-Tofu-Soymilk Desserts

Both wild (lowbush) blueberries (Vaccinium angustifolium Ait.) and soybeans (Glycine max L.) possess a variety of antioxidants, and both foods appear to have multiple health benefits. Our objectives were to identify whether wild blueberry juice concentrate was more acceptable than puree in frozen desserts with a soy milk‐tofu base; to determine whether fat‐free products were as acceptable as those with 10% added fat; and to compare several levels of blueberry juice concentrate. Four frozen dessert formulations were prepared in duplicate from soy milk, silken tofu, sucrose, stabilizer, BJC or puree, soybean oil or polydextrose, sweetened dried blueberries, salt, and lemon juice. Samples were assayed for total anthocyanins, antioxidant activity using the DPPH method, color, overrun, and solids. Fifty‐five persons evaluated the samples using a 9‐point hedonic scale for color, flavor, texture, and overall acceptability. Samples containing blueberry juice concentrate were darker and less blue. Anthocyanin levels were highest in the puree sample and the fat‐free product with 7.8% blueberry juice concentrate. However, antioxidant activity was highest (28 Trolox equivalents per gram) in the samples made with soybean oil and 7.4% blueberry juice concentrate. The puree formulation received higher hedonic scores than did the low‐fat blueberry juice concentrate formulations. The puree formulation received overall acceptability scores of like very much or like extremely by 45% of the consumers. These findings may aid processors in defining potential formulations that combine 2 healthful food ingredients.     

外源脱落酸处理对葡萄果实及葡萄酒中抗氧化成分的影响

以天津蓟州区栽培的"美乐"和"赤霞珠"葡萄为试验品种,分别在其始熟期的初、中和末期3个阶段利用外源脱落酸(200 mg/L)处理果实,采用分光光度法测定葡萄和葡萄酒中酚类总含量和抗氧化活性,利用液质联用技术分析花色苷的含量和组成.研究结果表明:始熟期的外源脱落酸处理对成熟果实的质量、可溶性固形物、可滴定酸和pH值,以及葡萄籽的酚类含量和抗氧化活性没有显著影响,但对葡萄皮和葡萄酒的酚类物质含量和活性具有显著影响.在始熟期中期(30％ ～50％果实转色)以前,对果实喷施外源脱落酸可以显著提高葡萄皮和葡萄酒的酚类总含量、花色苷总含量和抗氧化活性.始熟期外源脱落酸处理使"美乐"和"赤霞珠"果实的酚类总含量分别提高了14％ ～39％和73％ ～172％,花色苷总含量和抗氧化活性分别提高了18％ ～143％和88％ ～178％;外源脱落酸处理使葡萄酒的3个指标(酚类总含量、花色苷总含量和抗氧化活性)分别提高了17％ ～69％、18％ ～36％和21％ ～46％,而这些影响可以有效改善葡萄酒的感官品质和营养价值.外源脱落酸处理时期的精准控制可以提高酿酒葡萄及葡萄酒中酚类物质含量及抗氧化作用,进而提高葡萄酒品质和营养价值.     

Effects of exogenous abscisic acid on fruit quality, antioxidant capacities, and phytochemical contents of southern high bush blueberries

Abscisic acid (ABA) is a plant growth regulator that has a potential to increase antioxidant capacity and phenolic content of fruits and vegetables. The objective of this study was to examine whether an exogenous ABA application can positively affect fruit quality, antioxidant capacity, and phytochemical content of southern high bush blueberries (Vaccinium darrowii). Two varieties, namely Star and Windsor, were tested with ABA water solutions of three concentrations (0, 200, and 400 ppm) using a randomised complete block design. Results showed that ABA significantly increased the firmness of berries in both varieties, suggesting a ripening delay effect. Such effect was more pronounced in Windsor variety as reflected by a lower percentage of ripe berries and smaller sized berries on ABA treated bushes. In conclusion, ABA delayed the ripening of blueberries, but did not affect total phenolic content, antioxidant capacity, or the content of individual phytochemicals in ripe blueberries.     

不同制汁工艺对绿芦笋汁理化成分和抗氧化活性的影响

以绿芦笋为材料,研究了直接破碎制汁、热烫后破碎制汁、热烫后破碎经纤维素酶处理制汁、冷冻芦笋解冻后破碎制汁四种工艺对绿芦笋汁理化成分和抗氧化活性的影响。结果表明:热烫处理能保护芦笋汁的色泽,提高VC的稳定性;纤维素酶处理能提高芦笋汁的可溶性固形物、总糖及总黄酮含量及其抗氧化活性;热烫和纤维素酶处理均能降低芦笋汁中的可溶性蛋白和总酚含量。     

Anthocyanins,Antioxidative, and Antimicrobial Properties of American Cranberry (Vaccinium macrocarpon Ait.) and their Press Cakes

ABSTRACT: Amounts of total phenolics, anthocyanins, and ascorbic acid in 4 American cranberry varieties harvested at 4 stages of maturity were measured. The larger amount of phenolic compounds was found in berries of “Black Veil” cultivar (504 mg/100 g) at II stage of maturity. Significantly larger amounts of anthocyanins were determined in the overripe berries of the cultivars “Ben Lear” and “Black Veil.” The amount of ascorbic acid in berries increased during ripening from I to III stage, and slightly decreased in the overripe berries. The biggest quantities of ascorbic acid were found in the ripe berries of “Ben Lear” cultivar (15.8 mg/100 g). The distribution of anthocyanins pigments was determined by HPLC‐UV/MS in mature berries. The composition of individual anthocyanins in berries was quite similar in all the studied cranberry cultivars. While skins of cranberries are rich in anthocyanins and other phenolic compounds, the extracts of the by‐products of cranberries juice—berry cakes, were analyzed and obtained results were compared with the properties of extracts made from whole berries. The anthocyanins and total phenolics content, radical scavenging activity, antimicrobial activity of the whole berries, and their press cakes extracts were measured. All investigated extracts from berries and their press cakes showed good radical scavenging activity and revealed antimicrobial properties. It was found that Bacillus cereus (ATCC 10876) and Micrococcus luteus (ATCC 9341) were the most sensitive among 10 tested Gram‐negative and Gram‐positive bacteria.     

Comparison of polyphenolic composition and antioxidant activity of wild Italian blueberries and some cultivated varieties

Four varieties of cultivated blueberries (Vaccinium corymbosum) and a wild crop (Vaccinium miyrtillus) originating form the Modena region in Italy (Mirtillo nero dell’Appennino Modenese) and protected by the mark of origin, were examined in order to determine their antioxidant activity as related to their phenolic composition. The antioxidant activity was measured as radical scavenging activity, ferric reducing activity, and by an amperometric method; the total phenolics and total anthocyanins were determined by colorimetric methods; individual anthocyanins were evaluated by HPLC. Results showed that total phenolics and total anthocyanin concentrations were, respectively two fold and three fold higher in the wild fruits, which also had a higher anthocyanin-to-total phenolic ratio. Determination of individual anthocyanins put in evidence some differences between the cultivated and wild varieties, in particular the absence of acylated anthocyanins in wild blueberries. The antioxidant activity was much higher in wild blueberries than in the cultivated ones, and it was more related to the total phenolic rather that to the anthocyanin concentration.     

Antioxidant activity and antimicrobial effect of berry phenolics--a Finnish perspective

In Finland, berries are part of the traditional diet significantly contributing to the intake of flavonoids and other phenolic compounds. Compositional data on phenolic compounds in berries has been rapidly accumulating and included in the national food composition database. Among the different bioactive substances in berries, phenolic compounds including flavonoids, tannins, and phenolic acids have received considerable interest due to their effects in food and health. A great amount of in vitro evidence exists showing that berry phenolics are powerful antioxidants. However, the antioxidant effect of berry phenolics is strongly dependent on the choice of berry raw material, as the antioxidant activity differs between the different phenolic constituents, including anthocyanins, ellagitannins, and proanthocyanidins. In foods, the antioxidant effect is also influenced by the structure of food. Tannin-containing berries exhibit antimicrobial properties against pathogenic bacteria, thus offering many new applications for food industry. Much of the interest in berry phenolics has focused on cranberries and both cultivated and wild blueberries, although also other berries including black currants, cloudberries, lingonberries, and red raspberries possess promising bioactivities that may have relevance to human health. Antioxidant activity of berry phenolics, in addition to other mechanisms, may contribute to human health, but the possible relationship remains yet to be scientifically substantiated.     

Total Anthocyanins and Total Phenolics of Fresh and Processed Cherries and Their Antioxidant Properties

ABSTRACT: Total anthocyanins, total phenolics, and the antioxidant activities of 1 sour cherry cultivar ( Prunus cerasus L.) and 3 sweet cherry cultivars ( P. avium L.) were determined. Bing cherries were highest in anthocyanins, whereas Montmorency cherries were highest in total phenolics and antioxidant activities (oxygen radical absor-bance capacity and ferric reducing antioxidant power). Total phenolics and anthocyanins for all cultivars were concentrated in the skin. More than 75% of anthocyanins in frozen Bing cherries were destroyed after 6 mo of storage at -23°C. During canning, about half the anthocyanins and polyphenolics leached from the fruits into the syrup with little total loss. Spent cherry brine contained substantial anthocyanins and polyphenolics.     

Juice of New citrus hybrids (Citrus clementina Hort. ex Tan.×C. sinensis L. Osbeck) as a source of natural antioxidants

Fruit juices of pigmented and non-pigmented new citrus hybrids obtained by crossing clementine cv. Oroval with different cultivars of blood oranges were analysed to determine parameters related to fruit quality (total soluble solids titratable acidity, pH), and the content of ascorbic acid, total phenolics, flavanones, anthocyanins and phenolic acids. Antioxidant properties were evaluated by oxygen radical absorbance capacity (ORAC), and inhibition of induced linoleic acid peroxidation (InLAP) assays. The results of this study show that some hybrids with high antioxidant activity owing to considerable polyphenol content may be considered rich sources of phytochemicals. The OTA 9 hybrid was shown to be richest in polyphenols, suggesting that consumption of OTA 9 fruit or juice could be useful in health promotion and a disease-preventing diet. Moreover, the juice of this hybrid could be used as raw material to produce antioxidant ingredients for dietary, pharmaceutical, or cosmetic purposes.     

Antioxidant capacity and phenolic content in blueberries as affected by genotype and growing season

Blueberry fruits from five commercial cultivars and 13 breeding selections grown at the same locations over two growing seasons were analysed for total phenolics (TPH), total anthocyanins (ACY), total hydroxycinnamic acids (HCA), total flavonols (FLA), fruit weight and oxygen radical‐absorbing capacity (ORAC). Variation in ORAC, TPH, ACY, HCA, FLA and fruit weight among genotypes was much greater than that observed between growing seasons, indicating that genetics plays a more important role than growing season in influencing ORAC and phenolic content in blueberries. Significant main effects for growing season and genotype × growing season observed for ORAC, ACY, HCA and fruit weight demonstrate that environmental growing conditions can impact levels of phenolics and ORAC in blueberries and that certain genotypes vary in their capacity to synthesise phenolics under different growing conditions. In general, genotypes with smaller berries had higher ORAC values and levels of TPH, ACY, HCA and FLA than large‐berried genotypes. Over both growing seasons, ORAC correlated highly with TPH, ACY, HCA and FLA, while fruit weight correlated inversely with all phenolics measured. Our results indicate that blueberry genotypes should be screened over multiple growing seasons in order to identify antioxidant‐ and phenolic‐rich germplasm. Copyright © 2003 Society of Chemical Industry     

Antioxidant activity,anthocyanins, and phenolics of rabbiteye blueberry (Vaccinium ashei) by-products as affected by fermentation

Basic blueberry processing includes juice processing or winemaking. By-products obtained from the juice and wine industry can be a source of new value-added products such as phenolic antioxidant supplements or ingredients for food processing. The phenolic compositions of products and by-products (pomaces) depend mainly on processing techniques such as duration of skin contact, crushing, pressing, and others. The present study was to evaluate the effects of fermentation type on retention of total anthocyanins, total phenolics, and antioxidant activity of blueberry by-products. Total phenolics (TPH), total anthocyanins (ACY), antioxidant activities (β-carotene bleaching assay and ferric thiocyanate assay), and antiradical activity (DPPH radical-scavenging assay) of rabbiteye blueberry (Vaccinium ashei) by-products (juice, wine, and vinegar pomaces) were determined. The wine pomace (WP) had higher TPH, antioxidant activities and antiradical activity. Vinegar pomace (VP) had the lowest ACY, TPH, antiradical activity, and antioxidant activities. The results indicate that the antioxidant and antiradical activities of blueberry by-products were not significantly affected by the wine making process. Acetification significantly decreased TPH, ACY, antioxidant activities, and antiradical activity. However, VP still maintained an important phenolics concentration and antioxidant activity.     

蓝莓混汁加工中的防酶促褐变工艺

蓝莓含有大量的多酚氧化酶（PPO）,在果汁加工过程中易与酚类物质发生酶促褐变反应,影响果汁品质.榨汁前对蓝莓进行防褐变处理可以明显改善蓝莓混汁的品质,本文主要讨论了添加酶抑制剂和蒸汽热烫直接灭酶两种方法及其对果汁品质的影响.榨汁前添加0.05%VC可以抑制PPO与酚类物质反应,但不能使酶完全失活,且不能促进花色苷和多酚类物质的溶出;热烫2 min能使蓝莓的内源性PPO完全失活,防止酶促褐变,并且明显提高了果汁中的花色苷和总酚含量,提高果汁的色泽稳定性.     

超高压和高温短时杀菌对沙棘汁品质的影响

为了筛选出适合制汁的沙棘品种,对‘中国沙棘’‘圣果一号’‘深秋红’3 种沙棘的理化品质进行比较。结果表明,‘中国沙棘’具有最高的超氧化物歧化酶（superoxidative dismutase,SOD）活力（（1 029.14±77.72）U/g）、总酚含量（（8.37±0.20）mg GAE/g）及抗氧化能力（1,1-二苯基-2-三硝基苯肼自由基清除能力（11.04±0.27）mmol TE/100 g、铁离子还原抗氧化能力（6.06±0.32）mmol TE/100 g）。沙棘汁（经‘中国沙棘’制得,下同）经浓缩后SOD活力提高2.5 倍以上,可作为功能性产品。对超高压（high pressure processing,HPP）（500 MPa/6 min）或高温短时（high-temperature short-time,HTST）（100 ℃/15 s）处理后的沙棘汁品质进行了比较。两种处理都可以使沙棘汁中的菌落总数下降超过3（lg（CFU/mL））,且使霉菌和酵母无法检出。此外,两种处理均提高了沙棘汁中SOD的活性,其中HPP处理组的SOD活性在贮藏期间更高。两种处理均很好地保留了总酚、抗坏血酸含量及抗氧化能力,且这些品质指标在4 ℃冷藏期间同样得到很好的保留。综上,HPP和HTST处理的沙棘汁都是具有高SOD活性和抗氧化能力的产品。