Technological classification of basque cider apple cultivars according to their polyphenolic profiles by pattern recognition analysis

The polyphenolic compositions of 31 Basque cider apple cultivars were determined in pulp, peel, and juice by high-performance liquid chromatography--diode array detection analysis of crude extracts and after thiolysis. Data sets, consisting of individual polyphenol concentrations, total procyanidin content, and the average degree of polymerization of procyanidins, were evaluated by multivariate chemometric techniques, to develop decision rules for classifying apple cultivars technologically into bitter and nonbitter categories. A preliminary study of the data structure was performed by cluster analysis and principal component analysis in each apple material. Bitter apple varieties presented higher contents of flavan-3-ols and/or dihydrochalcones than nonbitter cultivars. Different classification systems for the two categories on the basis of the chemical data were obtained applying several supervised pattern recognition procedures, such as linear discriminant analysis, K-nearest neighbors, soft independent modeling of class analogy, partial least-squares, and multilayer feed forward artificial neural networks. Excellent performance in terms of recognition and prediction abilities for both categories (100% of hits) was achieved in every case (pulp, peel, or juice). Polyphenolic profiles of apple pulp, peel, or juice provide enough information to develop classification criteria for establishing the technological group of apple cultivars (bitter or nonbitter).     

Apple and pear peel and pulp and their influence on plasma lipids and antioxidant potentials in rats fed cholesterol-containing diets

The aim of this study was to assess the bioactive compounds of apple and pear peel and pulp in vitro and their influence on plasma lipids and antioxidant potentials in vivo. The antioxidant potentials measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), beta-carotene bleaching (beta-carotene), and nitric oxide inhibition radical scavenging (NO) tests in apple peel and pulp were significantly higher than in pear peel and pulp, respectively. The ethanol extract of apple peels showed the strongest inhibition of lipid peroxidation as a function of its concentration and was comparable to the antioxidant activity of butylated hydroxyanisole. The pear pulp extract had the weakest antioxidant ability, whereas other extracts such as apple pulp and pear peel were nearly equal. The antioxidant activities comprised contributions from polyphenols, phenolic acids, and flavonoids and correlated well with polyphenols and flavonoids. The correlation coefficients between polyphenols and antioxidant activities by DPPH, beta-carotene, and NO were as follows: 0.9207, 0.9350, and 0.9453. Contrarily, the correlation coefficient between the content of dietary fiber and the antioxidant activities test was low. The content of all studied indices in apple and pear peel was significantly higher than in peeled fruits (p < 0.05). Diets supplemented with fruit peels exercised a significantly higher positive influence on plasma lipid levels and on plasma antioxidant capacity of rats than diets with fruit pulps.     

Characterization of avocado (Persea americana mill.) varieties of low oil content.

Several avocado varieties of low oil content (6.73-8.07%) from Venezuela (Booth 1, Booth 7, Ceniap 2, Figueroa, Guacara Morado, Luiz de Queiroz, Princesa, Quebrada Seca, Santa Clara, Santa Cruz, Taylor, and Tonnage) were characterized for pulp oil and moisture; weight (whole fruit, seed, pulp, and peel); length, width, and fruit shape; peel characteristics (roughness, color, and hand peeling); and ripeness time. Oil plus moisture percentages were between 87.62 and 93.71. Pulp percentage of Quebrada Seca was the lowest of the 49 varieties studied, and its seed percentage the highest. Princesa had the highest pulp percentage (76%). Seven varieties were pyriform and five ovate, seven had rough peel and five smooth peel, and four of them had purple peel and the others green. Five varieties were easy to hand peel. Peak ripening of some varieties was at 4-9 days. Princesa is the variety with the highest potential yield with 67944 kg of fruit/ha, 51675 kg of pulp/ha, 3679 kg of oil/ha, and 3016 kg of starch/ha.     

Major phytochemicals in apple cultivars: contribution to peroxyl radical trapping efficiency

Forty-one samples of apples (peel plus pulp), obtained from eight cultivars, were examined for concentration of some important phytochemicals and for antioxidant activity expressed as peroxyl radical trapping efficiency. Five major polyphenolic groups plus ascorbate were identified and quantified by HPLC in the apple varieties. Oligomeric and polymeric proanthocyanidins were found to be about two-thirds of total polyphenols. The antioxidant efficiency of the apple extracts and of representative pure compounds for each group of phytochemicals was measured in a micellar system mimicking lipid peroxidation in human plasma. Although the amount of polyphenols measured by HPLC is similar to that measured by standard methods, the antioxidant efficiency calculated on the basis of the contribution of the pure compounds was lower than the antioxidant efficiency of the apple extracts. The higher efficiency of apples appears to be strictly related to the overwhelming presence of oligomeric proanthocyanidins.     

Polyphenolic profiles of Basque cider apple cultivars and their technological properties

The polyphenolic compositions of 31 Basque cider apple cultivars were determined in pulp, peel, and juice by high-performance liquid chromatography with diode array detection analysis of crude extracts and after thiolysis. Total polyphenols are distributed in a wide concentration range depending on the cultivar. Procyanidins are the class of polyphenols that present major concentrations in apple. Their average degrees of polymerization range from 4 to 8 depending on the cultivar. Apple cultivars were technologically classified into bitter and nonbitter categories using different classification systems obtained by applying several pattern recognition techniques, such as principal component analysis, K-nearest neighbors, soft independent modeling of class analogy, partial least-squares, and multilayer feed-forward-artificial neural networks, to apple pulp, peel, or juice data (individual polyphenol concentrations, total procyanidin content, and the average degree of polymerization of procyanidins). Bitter apple cultivars present higher contents of flavan-3-ols and/or dihydrochalcones than nonbitter cultivars. Detailed knowledge of the polyphenolic profile of each apple cultivar affords information about their susceptibility to oxidation, their sensory properties (bitterness, astringency), and their possible influence on the characteristics and quality of the final product (juice, cider) when apples are processed.     

Polyphenolic profiles in eight apple cultivars using high-performance liquid chromatography (HPLC)

Polyphenolic compounds of apple may play an important role in physiologic functions related to human health. Different polyphenolics may have varied biological activities including antioxidant activity. The objective of this study was to investigate the profiles of polyphenolic compounds in different apple varieties and different parts of an apple. The total and individual polyphenolics differed significantly among the eight apple cultivars grown in Ontario, and the peels had higher concentrations than the flesh. Among the tested cultivars, Red Delicious and Northern Spy had the highest concentrations and Empire the lowest. Five major polyphenolic groups with a total of 16 identified individual compounds were found, among which the dihydroxycinnamic acid esters, phloretin glycosides, and flavan-3-ols were found in both flesh and peel, whereas quercetin glycosides were almost exclusively found in the peel. Cyanidin 3-galactoside was unique to and found only in red apple peels. In both apple peel and flesh, the predominant group of polyphenolics was the procyanidins, followed by quercetin glycosides in the peel and hydroxycinnamic acid esters in the flesh. 3-Hydroxyphloretin 2'-xyloglucoside was newly identified in apple. The results obtained in this study will further the understanding of the polyphenolic composition of apples and their roles in health-promoting physiological functions.     

基于流变特性的不同品种苹果果皮质地评价

为探究苹果果皮表面碎裂损伤的原因和评价不同品种果皮的质地。采用电子万能试验机对丹霞、红富士和新红星苹果果皮进行拉伸松弛和蠕变特性试验,得到了果皮松弛的初始应力、残余应力、应变保持和蠕变的初始应变、应力保持、蠕变量;建立了苹果果皮松弛和蠕变的数学模型,对松弛和蠕变特性参数进行了相关性和主成分分析。结果表明:松弛和蠕变试验结果揭示出不同品种果皮的流变特性和内部组织结构存在差异。不同品种果皮的初始应力较大时,松弛平衡后的残余应力较大;初始应变较大时,蠕变量较小。新红星果皮的弹性因子贡献率较高,而红富士果皮的黏性因子贡献率较高,反映出红富士果皮表面中较新红星和丹霞果皮表面容易碎裂损伤,在采收、运输等过程中红富士的果皮较新红星和丹霞的果皮易受机械损伤。研究结果可为苹果品种的优育及其质地评价体系的建立和完善提供参考。     

Antioxidant activity of apple peels

Consumption of fruits and vegetables has been shown to be effective in the prevention of chronic diseases. These benefits are often attributed to the high antioxidant content of some plant foods. Apples are commonly eaten and are large contributors of phenolic compounds in European and North American diets. The peels of apples, in particular, are high in phenolics. During applesauce and canned apple manufacture, the antioxidant-rich peels of apples are discarded. To determine if a useful source of antioxidants is being wasted, the phytochemical content, antioxidant activity, and antiproliferative activity of the peels of four varieties of apples (Rome Beauty, Idared, Cortland, and Golden Delicious) commonly used in applesauce production in New York state were investigated. The values of the peels were compared to those of the flesh and flesh + peel components of the apples. Within each variety, the total phenolic and flavonoid contents were highest in the peels, followed by the flesh + peel and the flesh. Idared and Rome Beauty apple peels had the highest total phenolic contents (588.9 +/- 83.2 and 500.2 +/- 13.7 mg of gallic acid equivalents/100 g of peels, respectively). Rome Beauty and Idared peels were also highest in flavonoids (306.1 +/- 6.7 and 303.2 +/- 41.5 mg of catechin equivalents/100 g of peels, respectively). Of the four varieties, Idared apple peels had the most anthocyanins, with 26.8 +/- 6.5 mg of cyanidin 3-glucoside equivalents/100 g of peels. The peels all had significantly higher total antioxidant activities than the flesh + peel and flesh of the apple varieties examined. Idared peels had the greatest antioxidant activity (312.2 +/- 9.8 micromol of vitamin C equivalents/g of peels). Apple peels were also shown to more effectively inhibit the growth of HepG(2) human liver cancer cells than the other apple components. Rome Beauty apple peels showed the most bioactivity, inhibiting cell proliferation by 50% at the low concentration of 12.4 +/- 0.4 mg of peels/mL. The high content of phenolic compounds, antioxidant activity, and antiproliferative activity of apple peels indicate that they may impart health benefits when consumed and should be regarded as a valuable source of antioxidants.     

砀山梨果多酚氧化酶活性的分析

为探讨梨果多酚氧化酶(polyphenol oxidase,PPO)活性变化规律,本研究选取贡梨、酸梨、紫酥梨、香梨、酥梨和皇冠梨6个不同品种的砀山梨果作为实验材料,采用分光光度计法分别测定了梨果的皮、肉和心的多酚氧化酶活性,并对其进行分析。结果表明,紫酥梨皮、香梨肉和香梨心PPO活性最高,分别为19.72AU·g-1·min-1、19.51AU·g-1·min-1和19.30AU·g-1·min-1,酸梨皮、酸梨肉以及皇冠梨心的PPO活性最低,分别只有11.64AU·g-1·min-1、13.39AU·g-1·min-1和6.67AU·g-1·min-1。PPO活性变异及方差分析显示,梨皮PPO活性平均值最高为16.27AU·g-1·min-1,梨心PPO活性平均值最低为13.68AU·g-1·min-1;不同品种梨皮、梨肉、梨心PPO活性变化不一致;不同部位中梨心的PPO活性变异系数最大,达32.23%;不同部位及品种间PPO活性差异不显著。由此可知梨皮可以作为梨果PPO活性改良的目标之一,梨心具有筛选低PPO活性的潜力,皇冠梨梨心可作为选育低PPO活性的种质资源。     

Apple pomace is a good matrix for phytochemical retention

Phytochemical content and color changes in dried apple pomace and pulp (mixture of Red Delicious and Golden Delicious varieties) were studied during 9 months storage in the water activity (a(w)) range 0.11-0.75 at 30 °C. Water mobility was measured at various a(w) levels by (1)H NMR. During storage, antioxidant degradation (including flavonols, flavanols, dihydrochalcones, anthocyanins, and hydroxycinnamic acids) followed first-order kinetics, whereas color changes followed zero-order kinetics. These changes were accelerated by increasing a(w). Phytochemical and color were more stable in the pomace than in the pulp over the entire a(w) range, having 2-6 times smaller degradation rates. These results were related to the lower water mobility found in apple pomace as compared to the pulp. The overall results show that apple pomace can be exploited as a food ingredient with good phytochemical retention, and may help in the development of new matrices with maximum phytochemical retention.     

Comparative analysis of polyphenolic profiles and antioxidant and antimicrobial activities of tunisian pome fruit pulp and peel aqueous acetone extracts

Pome trees, apple, pear, and quince, are classified into the subfamily Pomoideae, belonging to the Rosaceae family. Their autumnal fruits are consumed worldwide in different forms, that is, fresh or transformed into jams, jelly, juices, etc. Their well-established beneficial properties to human health were found mainly related to their phenolic content. Pulp and peel aqueous acetone extracts obtained from Tunisian fruits at commercial maturity were comparatively evaluated for their phenolic profiles and antioxidant and antimicrobial potentials. The phenolic compounds present in the extracts were identified and quantified using RP-HPLC-DAD and ESI-MS techniques. Significant differences in the chromatographic profiles among these fruits, as well as between pulp and peel extracts of each fruit, were observed. Quince, followed by 'Red Delicious', peel extracts showed the highest phenolic content (160.33 and 110.90 mg/100 g of fresh weight). The stronger inhibitory effect on DPPH radicals corresponded to those obtained from peel materials. A comparative analysis of the antimicrobial potential against a range of microorganism strains was also carried out. Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus were the most sensitive to the active extracts. Among the examined phenolic extracts, 'Red Delicious' and quince peels showed the highest effects for inhibiting bacteria growth. Minimum inhibitory and bactericide concentrations ranged from 10(2) to 10(4) microg of polyphenol/mL. Red skin apple and quince peels could be of great interest as important antioxidant and antimicrobial polyphenol sources.     

Improved HPLC determination of phenolic compounds in cv. golden delicious apples using a monolithic column

A rapid HPLC-DAD determination of phenols in apple using an RP monolithic column is reported. Because of the hydrodynamic advantages offered by this kind of column and the use of acidified acetonitrile as eluent, assays of apple extracts can be performed in <21 min. Assays of pulp and peel extracts were carried out without the need for time-consuming sample pretreatment except filtration. Several flavanols, hydroxycinnamic acids, dihydrochalcones, and six quercetin glycosides were identified and quantified. A seventh quercetin derivative, two chalcone-related compounds, and three hydroxycinnamic derivatives were also found. Peels proved to be richer in phenols than pulps, the former being composed mainly of (-)-epicatechin, procyanidin B2, chlorogenic acid, phloridzin, hyperin, and avicularin. In pulps, where the chlorogenic acid was the principal phenolic compound, quercetin glycosides were found in very low amounts.     

Oil goldenberry (Physalis peruviana L.)

Whole berries, seeds, and pulp/peel of goldenberry (Physalis peruviana L.) were compared in terms of fatty acids, lipid classes, triacylglyerols, phytosterols, fat-soluble vitamins, and beta-carotene. The total lipid contents in the whole berries, seeds, and seedless parts were 2.0, 1.8, and 0.2% (on a fresh weight basis), respectively. Linoleic acid was the dominating fatty acid followed by oleic acid as the second major fatty acid. Palmitic and stearic acids were the major saturates. In pulp/peel oil, the fatty acid profile was characterized by higher amounts of saturates, monoenes, and trienes than in whole berry and seed oils. Neutral lipids comprised >95% of total lipids in whole berry oil and seed oil, while neutral lipids separated in lower level in pulp/peel oil. Triacylglycerols were the predominant neutral lipid subclass and constituted ca. 81.6, 86.6, and 65.1% of total neutral lipids in whole berry, seed, and pulp/peel oils, respectively. Nine triacylglycerol molecular species were detected, wherein three species, C54:3, C52:2, and C54:6, were presented to the extent of approximately 91% or above. The highest level of phytosterols was estimated in pulp/peel oil that contained the highest level of unsaponifiables. In both whole berry and seed oils, campesterol and beta-sitosterol were the sterol markers, whereas Delta5-avenasterol and campesterol were the main 4-desmethylsterols in pulp/peel oil. The tocopherols level was much higher in pulp/peel oil than in whole berry and seed oils. beta- and gamma-tocopherols were the major components in whole berry and seed oils, whereas gamma- and alpha-tocopherols were the main constituents in pulp/peel oil. beta-Carotene and vitamin K(1) were also measured in markedly high levels in pulp/peel oil followed by whole berry oil and seed oil, respectively. Information provided by the present work is of importance for further chemical investigation of goldenberry oil and industrial utilization of the berries as a raw material of oils and functional foods.     

Apple peel as a contributor to whole fruit quantity of potentially healthful bioactive compounds. Cultivar and year implication

On the basis of the fresh weight of apple fruit and its peel and the concentration of bioactive compounds, the total quantity of L-cysteine, glutathione, ascorbate, flavonols, and anthocyanins as well as phenolics was evaluated in a wide range of cultivars and two growing seasons. Apple peel as a contributor to the entire apple quantity of the examined components considerably differed in relation to the investigated compounds and was also highly cultivar dependent. A great amount of flavonols was found in apple peel (approximately 40%), followed by ascorbate (approximately 30%) and total phenolics (approximately 20%), while the lowest contribution was assessed for thiols (approximately 11% and 14% for L-cysteine and total quantity of glutathione, respectively), based on average values for both years. Seasonal variations in the quantity of antioxidants was more pronounced in apple peel, whereas the contribution of apple peel to the whole fruit was predominantly affected by the genotype. A very high positive correlation existed between apple peel and the whole fruit quantity of antioxidants.     

Flavonoids in vegetable foods commonly consumed in Brazil and estimated ingestion by the Brazilian population

The objective of this work was to quantify the flavonoids present in foods most commonly consumed by the Brazilian population. The predominant flavonoids found in largest abundance in all of the analyzed vegetables were glycosides of quercetin. In lettuce, a small amount of luteolin was also detected. In sweet pepper, quercetin and luteolin were both present. White onion [48-56 mg/100 g of fresh weight (FW), expressed as aglycon], red onion (40-100 mg/100 g of FW), red lettuce (67-67.2 mg/100 g of FW), arugula (41-118 mg/100 g of FW), and chicory (18-38 mg/100 g of FW) were highest in total flavonoids. In fruits, the highest concentrations of flavonoids were found in the peel (125-170 mg/100 g of FW) and pulp (35-44 mg/100 g of FW) of oranges and in some apple varieties (14-36 mg/100 g of FW). Variability in flavonoid content due to time of harvesting was high for leafy vegetables and red onions. The estimated ingestion by Brazilian population ranged from 60 to 106 mg/day.     

Influence of cultivar, harvest time, storage conditions, and peeling on the antioxidant capacity and phenolic and ascorbic acid contents of apples and pears

Apple and pear fruits are important sources of secondary plant metabolites and one of the major sources of dietary phenolics consumed all year round. The aim of this work was to identify the main variables influencing phenolic content and antioxidant capacity in apples. Higher phenolic and antioxidant contents were observed in some varieties (such as the Delbar Estival apple and Durondeau pear). Storage conditions were important. Our results also showed that fruits should be consumed rapidly after purchase and with their peel. After one week of domestic storage, the ascorbic acid content was found to decrease by 75%. Peeling led to a more than 25% decrease in total phenolics and ascorbic acid. The harvest time (at normal ripeness) had only a limited impact, but significant year-to-year variations were observed. In conclusion, well-chosen and well-stored apples and pears may contribute to an antioxidant-rich diet if consumed rapidly and with their peel.     

Fate of apple peel phenolics during cool storage

Consumption of certain phenolics in the diet is considered beneficial to human health. In this study, individual phenolics were measured by diode-array HPLC at monthly intervals in the peel of Granny Smith, Lady Williams, and Crofton apple cultivars stored in air at 0 degrees C for 9 months. The concentrations of total phenolics significantly differed among the cultivars examined, with Lady Williams peel having significantly more phenolics (over 4000 microg x g(-1) peel fresh weight) than Crofton (2668 microg x g(-1) peel fresh weight) and Granny Smith, which had the lowest concentration of total phenolics (1275 microg x g(-1) peel fresh weight). There were also significant differences in individual phenolics among cultivars and during storage. Quercetin glycosides were the only flavonols identified, with quercetin rhamnoglucoside being the most abundant phenolic in the peel. Chlorogenic acid was the major cinnamic acid derivative, with high concentrations, up to 412 microg x g(-1)) peel fresh weight, in Crofton peel. A pre-storage diphenylamine (DPA) treatment had few significant effects on peel phenolic metabolism. Where differences did occur, fruit treated with DPA retained higher concentrations of total peel phenolics during storage than fruit not treated with DPA. Storage of all cultivars for up to 9 months in air at 0 degrees C induced few significant changes in the peel phenolic concentrations. This indicates that phenolic metabolism in apple peel is relatively stable, and the health benefits of phenolics in apple peel should be maintained during long-term storage.     

沙田柚果实贮藏期水分变化与枯水的关系

沙田柚采后经１０ｄ预贮藏于常温室内,用＾３Ｈ２Ｏ示踪,定期测定果蒂部、果皮,果肉（汁胞）的放射性比活度和果实的失重率,果汁率,组织含水量,呼吸速率及营养物质含量变化,结果表明,沙田柚贮藏期间,果瓣之间,果肉和果皮之间水分是相互流动的,果实枯水时,水分从果肉到果皮的转移速度大于正常果,沙田柚果实枯水的原因可能与果肉营养物质消耗和果皮组织相对再生长同步进行有关。     

Relationship between apple peel and the whole fruit antioxidant content: year and cultivar variation

Antioxidants are usually considered with regard to plant defense mechanisms due to the oxidative stress or their importance for human health or both. In the present research, a comprehensive study was made to test the relationship between the antioxidant content in apple peel and the whole fruit in two growing seasons. Antioxidants were mainly localized in the apple peel, but cultivars exhibited very high biodiversity in the distribution pattern. High or very high correlation coefficients between apple peel glutathione reductase and catalase activity as well as ascorbate, glutathione, and anthocyanins concentrations and the whole fruit were discovered on the basis of both fresh and dry weight basis in two growing seasons: 2004 and 2005. In the case of ascorbate peroxidase activity and phenolics or flavonol contents, it was proven only in 2005. It seems that apple peel could be a good marker of health values as well as antioxidant potential of apple fruit. Additional arguments, as compared to the previous study, were incorporated to support the suggestion of glutathione reductase as worth considering as an environmental stress marker and/or signalling molecule.     

果皮和果肉比例对真空冷冻干燥重组芒果脆块品质的影响

芒果皮富含膳食纤维、类胡萝卜素等生物活性化合物,但在食品工业中尚未被充分利用。为了实现芒果资源的全利用,本研究制备了含不同比例果皮和果肉的真空冷冻干燥重组芒果脆块,并考察了脆块的玻璃化转变温度(T_g)、质构、微观结构、类胡萝卜素含量等品质,综合分析了果皮和果肉比例对脆块理化、质构、营养和感官品质的影响。结果表明,添加芒果皮后脆块的硬度提高了2.65%～24.07%。当果皮含量超过20%时,脆度呈下降趋势,下降了1.91%～73.49%。此外,添加芒果皮后脆块的总酚、类胡萝卜素和膳食纤维含量分别增加了60.96%～336.75%、11.17%～112.48%和28.61%～166.36%。感官评价结果表明,芒果皮添加比例为40%以内的脆块综合品质得分均较高。综合考虑,添加20%芒果皮既可显著提高脆块的营养功能特性,改善质构稳定性,又具有较佳的综合感官品质。本研究结果表明,基于质构重组和真空冷冻干燥技术制备复合脆块是实现芒果皮资源利用的一种可行方法,这为生产中芒果皮的利用和添加量的选择提供了理论依据。