Effects of Seasonal Variation on Sensory Properties and Total Phenolic Content of 5 Lettuce Cultivars

ABSTRACT: Butterhead, crisphead, green leaf, red leaf, and romaine types of lettuce (Lactuca sativa L.) are all commonly available in U.S. markets. Sensory properties of lettuce may vary in response to environmental factors that often fluctuate widely throughout the growing season. Bitterness is generally thought to increase in lettuce grown at higher temperatures and may be related to phenolic content. This study evaluated sensory properties and total phenolic content of 5 lettuce cultivars harvested early, midway, and late in the growing season and investigated possible correlations with environmental temperature and light intensity indexes. Thirty panelists rated bitterness, appearance, flavor, texture, and overall acceptability of “Crisp and Green” (green leaf), “Crispino” (crisphead), “Green Forest” (romaine), “Lochness” (butterhead), and “Vulcan” (red leaf) lettuce. There was considerable variation in sensory ratings among the 5 cultivars (P < 0.005) but few differences within cultivars across the growing season. The crisphead cultivar, Crispino, received higher scores (P < 0.01) for flavor, texture, and overall acceptability and was rated less bitter (P < 0.05) than other cultivars. Total phenolic content varied significantly (P < 0.001) among cultivars with the red leaf cultivar, Vulcan, exhibiting the highest levels. There was no correlation between bitterness and total phenolic content or environmental factors. Differences among lettuce cultivars appear to have a larger impact on sensory and phenolic profiles than environmental variation during the growing season.     

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.     

Liaison of phenolic acids and biological activity of escalating cultivars of Daucus carota

The objective of the present study was to analyze and compare the phenolic compounds and their antioxidant capacities of new lines of Dacus carota. The selected cultivars showed high variation in the contents of total phenolics (30.26–65.39 mg/100 g FW) and total ascorbic acid (41.12–58.36 mg/100 g FW). Analysis on RP-HPLC revealed that hydroxycinnamic acids and its derivatives were major phenolic compounds present in D. carota extracts, whereas 5-caffeolquinic acid was a major hydroxycinnamic acid (ranged from 30.26 to 65.39 mg/100 g FW). DCP cultivar showed high total antioxidant capacity (77.69 mg/100 g), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity (52.36 mg/100 g), superoxide radical scavenging capacity (53.69 mg/100 g), and hydroxyl radical scavenging capacity (51.91 mg/100 g). A linear relationship was found between total phenolic acid contents and antioxidant capacity. Both phenolic compounds and antioxidant capacities varied significantly (ρ < 0.05) among cultivars. DCP cultivar was found to be a rich source of phenolics and ascorbic acid with high antioxidant activity.     

CULTIVAR AND HARVEST DATE EFFECTS ON FLAVOR AND OTHER QUALITY ATTRIBUTES OF CALIFORNIA STRAWBERRIES

“Aromas,”“Diamante” and “Selva” strawberries were harvested in early and mid‐season and evaluated for quality attributes, flavor components, fermentative metabolites and physiological characteristics. Preference and flavor tests by consumer panels were also conducted. Cultivar variation was greater than harvest date variation as were differences in color, concentrations of anthocyanins, firmness, total soluble solids, sugars, pH, titratable acidity (TA), organic acids and aroma compounds. “Diamante” and “Selva” had higher aroma quality than “Aromas” fruits. The levels of fermentative metabolites were too low to have an impact on the aroma quality. “Diamante” and “Selva” strawberries had better overall flavor quality and were more preferred by consumers than “Aromas.” These differences were consistent over two harvest dates.     

Changes of Bioactive Compounds and Ethylene Production of Japanese Plums Treated with Pre-Harvest Aminoethoxyvinylglycine

The effects of pre-harvest aminoethoxyvinylglycine treatments on bioactive compounds, fruit ripening, and quality of plum fruits (Prunus salicina Lindell cvs. “Black Beauty,” “Black Amber,” and “Friar”) were investigated in this research. Whole trees were sprayed once with an aqueous solution containing aminoethoxyvinylglycine (0, 100, and 200 mg L^–1) two weeks before the anticipated commercial harvest for each cultivar separately. In all plum cultivars, the results showed that aminoethoxyvinylglycine treatments were effective in reducing ethylene production and respiration rate. The red color development was delayed by aminoethoxyvinylglycine treatments during the ripening. The fruit mass and geometric mean diameter significantly decreased, while loss of flesh firmness was decelerated with aminoethoxyvinylglycine concentrations. Aminoethoxyvinylglycine treatments decelerated loss of flesh firmness. Soluble solid content was reduced, whereas titratable acidity and ripening index increased with aminoethoxyvinylglycine treatments. Aminoethoxyvinylglycine-treated fruits exhibited lower levels of total phenolics, total antioxidant activity, and individual phenolics. This study revealed that pre-harvest aminoethoxyvinylglycine treatments were more effective in delaying plum fruit softening. The main advantage is to maintain the firmness of late-harvested fruit by retaining bioactive compounds of plum fruit.     

The effect of cooking on the location and concentration of oxalate in three cultivars of New Zealand‐grown oca (Oxalis tuberosa Mol)

Oca (Oxalis tuberosa Mol) originates from South America but is now also grown commercially in New Zealand. It contains moderate amounts of oxalate, which is only present in its soluble form. The skin of the oca tuber is thought to contain more oxalate than the flesh. In this study the concentration of soluble oxalate was measured in the skin and outer and inner flesh and in the whole tuber of raw, boiled, baked and steamed oca. The analysis was carried out on the traditionally pinkish‐red New Zealand cultivar and on the newly introduced cultivars ‘Mellow Yellow’ and ‘Apricot Delight’. In the raw oca tuber the oxalate concentration in the skin is significantly higher than in the flesh (mean value 7.3 g kg^?1 fresh weight (FW) compared to 1.7 and 1.4 g kg^?1 FW in the outer and inner flesh respectively). The highest concentration was found in the skin of the pinkish‐red cultivar (10.9 ± 1.0 g kg^?1 FW). All cooking methods seemed to cause a migration of oxalate from the skin to the underlying flesh. On a fresh weight basis, baking significantly increased the oxalate concentration in the whole tuber, whereas boiling decreased the concentration and steaming had no significant effect (p < 0.001). Boiling might therefore be a better way of cooking oca than baking when a low intake of oxalate is desired. © 2001 Society of Chemical Industry     

Vital Characteristics of Litchi (Litchi chinensis Sonn.) Pericarp that Define Postharvest Concepts for Thai Cultivars

To assess the fruit-specific determinants of pericarp browning, litchi pericarp was characterized in terms of appearance, the polyphenol pattern as specified by HPLC-DAD-MS ⁿ without and after thiolysis, and the activities of polyphenol oxidase (PPO) and peroxidase (POD) by exploring “Kwang Jao,” “O-Hia,” “Kim Cheng,” and “Chacapat” fruit on the respective harvest day, “Hong Huey” fruit also throughout 52 days of cold storage (5 °C, 95% relative humidity). At harvest, PPO activity was maximum for “Kim Cheng” pericarp (126 μkat/hg), whereas POD activity was striking for that of “O-Hia” (512 μkat/hg, including membrane-bound isoforms). Flavan-3-ol and proanthocyanidin patterns were consistent for all cultivars. However, cultivars with sharp-pointed and round–obtuse protuberances differed in pericarp anthocyanin and flavonol glycosylation patterns. The molar ratio of cyanidin 3-O-rutinoside to its glucoside was ≤6:1 for “Hong Huey” and “Kwang Jao,” but ≥43:1 for “Kim Cheng” and “Chacapat” pericarp. Long-term storage gave evidence of two key processes involved in pericarp browning: (1) PPO-mediated oxidation of abundant (?)-epicatechin (1.4–2.0 g/hg), resulting in dark brown pigments, and (2) microcrack-induced formation of light brown surface scurf, supposably with involvement of POD. Accordingly, an improved scheme for litchi pericarp browning was proposed. As regards recommendable postharvest concepts for each cultivar, “Chacapat” suited most for long-distance transports due to its overall low susceptibility to pericarp browning. Properties of “O-Hia” litchi, being prone to surface scurf formation, suggested preferred distribution via domestic markets. High contents of flavonols (e.g., quercetin glycosides, 166 mg/hg) and A-type-linked procyanidins (e.g., procyanidin A2, 1,092 mg/hg) qualified pericarp of “Hong Huey” litchi as raw material for polyphenol extracts exerting antioxidant properties.     

ANTIOXIDANT CAPACITY,SCAVENGING RADICAL ACTIVITY AND SELECTED CHEMICAL COMPOSITION OF NATIVE APPLE CULTIVARS FROM CENTRAL EUROPE

ABSTRACT

The main aim of this study was to focus on 10 typical native apple cultivars from Central Europe and to determine the basic characteristics such as dry matter, soluble solid content, titrable acidity, the content of pectins, phenolics, ascorbic acid, antioxidant capacity and the scavenging effect of 10% apple fruit extracts on hydroxyl radical, nitric oxide and superoxide radical in them. In our experiments, it was found out that the highest content of organic acids was shown by the “Jeptiska” cultivar (5.40 g/kg of FM). As far as the content of pectins was concerned, the highest levels were found out in the “Strymka” cultivar (32.60 g/kg FM). In case of total phenolic content, antioxidant capacity, ascorbic acid content and scavenging activity of reactive oxygen species (hydroxyl radical, nitric oxide and superoxide anion), high efficiency was determined in the local cultivars, namely, in “Matcino,”“Panenske ceske” and “Strymka.”

PRACTICAL APPLICATIONS

The results shown have wide use in the alimentary industry and human nutrition as apples belong to the most widespread core fruit. There exist many apple cultivars that have not been described in detail in literature and this study provides an insight into 10 not very common cultivars in the world; and although in Central Europe these cultivars are cultivated successfully, so far they have not been utilized commercially. However, their genetic uniqueness represents an irreplaceable ecological wealth and for that reason these local cultivars could become a new and outstanding source of nutrients and food. Today, they can also be used as a potential material for further breeding and selection.     

Total Phenolics,Carotenoids, Ascorbic Acid,and Antioxidant Properties of Fresh‐cut Mango (Mangifera indica L., cv. Tommy Atkin) as Affected by Infrared Heat Treatment

Abstract: Mango (Mangifera indica L.) is a major tropical fruit that has not been exploited for fresh‐cut or minimally processed products on a scale similar to apples, pineapples, or melons. The objective of this study was to investigate the effect of infrared (IR) treatment on total phenolics, carotenoids, ascorbic acid, and antioxidant properties of fresh‐cut cubes from ‘Tommy Atkin’ mangoes. Mango cubes were IR treated (5, 10, 15 min) and evaluated at 4‐d intervals during 16‐d storage at 4 ± 1 °C. Total phenolics, carotenoids, and ascorbic acid content in fresh‐cut control mango cubes were 43.33, 1.37, and 15.97 mg/100 g FW, respectively. IR treatments increased total phenolics (59.23 to 71.16 mg/100 g FW) and decreased ascorbic acid (12.14 to 15.38 mg/100 g, FW). Total carotenoids showed a mixed trend (1.13 to 1.66 mg/100 g, FW). The IR treatment showed a significant positive impact on antioxidant properties (μM TE/100 g, FW) of mango cubes, as assayed by ABTS (261.5 compared with 338.0 to 416.4), DPPH (270.5 compared with 289.4 to 360.5), and ORAC (6686 compared with 8450 to 12230). Total phenolics, carotenoids, ascorbic acid, and antioxidant capacity decreased over 16‐d storage. However, IR treated samples had consistently higher ABTS, DPPH, and total phenolics during storage. It was demonstrated that IR treatment can be effectively used in improving antioxidant properties of fresh‐cut mangoes with minimal effect on the visual appearance. Practical Application: Various methods/treatments are in use for extending the quality of fresh‐cut fruits, including mild heat treatment. This study explored the application of infrared (IR) heat for processing fresh‐cut mango cubes and evaluated its effect on vitamin C and antioxidant capacity during 16‐d storage. This is the first study reporting on the use of IR heat in fresh‐cut fruits. IR treatment was shown to be effective in retaining antioxidant properties of fresh‐cut mango cubes with minimal effect on the visual appearance.     

Effects of Low-dose Electron Beam Irradiation on Respiration, Microbiology, Texture, Color, and Sensory Characteristics of Fresh-cut Cantaloupe Stored in Modified-atmosphere Packages

Fresh‐cut cantaloupe was placed in modified‐atmosphere packages (4% oxygen, 10% carbon dioxide) and irradiated at 0 (control), 0.5, and 1.0 kGy. Irradiated samples had a lower and more stable rate of respiration than non‐irradiated samples over about 20 d. Total plate counts were higher (P < 0.05) in non‐irradiated control samples through day 11 (Trial 1) and for all dates tested (Trial 2). Color and texture remained stable for the duration of each study as measured by instruments and trained sensory panels. Sensory evaluation rated the 1.0‐kGy sample highest in “sweetness” and “cantaloupe flavor intensity” and lowest in “off‐flavor” after 17 (±3) d of storage. Low‐dose electron beam irradiation of fresh‐cut cantaloupe with modified‐atmosphere packaging offers promise as a method of extending shelf life.     

Evaluating taste contribution of brown sugar in chicken seasoning using taste compounds,sensory evaluation,and electronic tongue

In this study, the taste contribution of brown sugar in chicken seasoning was evaluated. Chicken seasonings containing brown sugar (AB), white sugar (AW), and liquid sugar (AL) were compared by the detection of taste compounds, sensory evaluation, and electronic tongue measurements. The correlation model of the three kinds of data was built by partial least squares regression (PLSR). The contents of the taste compounds in sample AB was higher than in sample AW and lower than in sample AL. Sample AB had the strongest “umami” and “full-body” taste and the highest response values for the UMS and GPS sensors. Combined with the PLSR results, brown sugar could be used to balance the taste of chicken seasoning. In conclusion, brown sugar had a positive effect on flavor quality and could help to improve chicken seasoning recipes.     

Carotenoid Profile,Total Phenolic Content,and Antioxidant Activity of Carrots

Carotenoid profile, antioxidant activity, and total phenolic content of carrot cultivars from three different locations in Turkey were determined during two consecutive years. The major carotenoids determined in carrots were β-carotene (41.60–71.2 mg/kg FW) and α-carotene (13.44–30.11 mg/kg FW). The total phenolic contents of carrots ranged from 114–306 mg catechin/kg FW. The antioxidant activity in carrots determined by the TEAC assay varied between 25.9 and 86.6 μmol TE/100 g FW. There was considerable variation in carotenoid contents between locations and years among cultivars. Significant differences were found between the two consecutive years in total phenolic contents except for only one cultivar. The level of antioxidant activity in carrots varied significantly over the years.     

Characterization of Shortday Onion Cultivars of 3 Pungency Levels with Flavor Precursor, Free Amino Acid, Sulfur, and Sugar Contents

ABSTRACT:  This study was conducted to characterize shortday onions of 3 pungency levels with regard to the composition of flavor related compounds. A total of 9 onion breeding lines/cultivars were selected, per each of low, medium, and high pungency level, with pyruvic acid contents of 1.9 to 2.8, 4.8 to 5.4, and 7.2 to 8.3 μmoles/mL, respectively. The contents of flavor precursors (S-1-propenyl-L-cysteine sulfoxide [1-PeCSO] and S-methyl-L-cysteine-sulfoxide [MCSO]), free amino acids, free sugars, soluble solids (SSC), and total sulfur (S) in onion bulbs were measured. The flavor precursor contents ranged from 0.03 to 0.16 mg/g fresh weight (FW) for MCSO, 0.07 to 0.65 mg for 1-PeCSO, and 0.12 to 0.77 mg in total, and precursor contents increased with the pungency levels. Onions of different pungency levels did not differ in the contents of individual or total free amino acids, and the most abundant amino acids were glutamine and arginine. The total sugar contents ranged from 50 to 75 mg/g FW, and total S contents (3.5 to 5.1 mg/g dry weight) were not correlated with the pungency levels. However, pungency levels were correlated inversely with bulb weight and positively with SSC, presumably by the effect of dilution. This study indicates that onion pungency is primarily determined by the content of flavor precursor compounds and not by total S, total sugars, or individual/total free amino acids in shortday bulbs.     

Sugars,organic acids,phenolic composition and antioxidant activity of sweet cherry (Prunus avium L.)

Sugars, organic acids, phenolics and anthocyanins in fruits of 13 sweet cherry cultivars: Badascony, Burlat, Early Van Compact, Fercer, Fernier, Ferprime, Lala Star, Lapins, Noire de Meched, Sylvia, Vesseaux, Vigred (red-coloured) and Ferrador (bi-coloured) were quantified by HPLC. Sweet cherry cultivars of different pomological characteristics and different time of ripening were evaluated sensorily. Cultivars were evaluated for their total phenolic content and antioxidant activity. The sum of sugars (glucose, fructose, sucrose and sorbitol) ranged from 125 to 265 g/kg fresh weight (FW) and the sum of organic acids (malic, citric, shikimic and fumaric) ranged from 3.67 to 8.66 g/kg FW. Total phenolic content ranged from 44.3 to 87.9 mg gallic acid equivalents/100 g FW and antioxidant activity ranged from 8.0 to 17.2 mg ascorbic acid equivalent antioxidant capacity mg/100 g FW. The correlation of antioxidant activity with total phenolics content and content of anthocyanins was cultivar dependent.     

Sheep milk kefir sweetened with different sugars: Sensory acceptance and consumer emotion profiling

The objective of this study was to determine the sensory acceptance and emotional profile of sheep milk kefir sweetened with different sugars (demerara sugar, brown sugar, fructose, coconut sugar, and honey, 100 g/L). Consumers (n = 100) assessed sensory acceptance (appearance, aroma, taste, texture, and overall impression), and expressed their emotions (satisfied, active, loving, calm, comfortable, energetic, happy, healthy, refreshing, disgusted, worried, and upset). The emotions “satisfied,” “active,” “comfortable,” “energetic,” “healthy,” and “refreshing” were found between moderate and very high levels, indicating that they are important emotions for the characterization and sensory acceptance of kefir samples. The use of different sugars had no influence on the intensity of the emotions “calm,” “comfortable,” “happy,” or “disgusted,” and resulted in a greater sense of satisfaction. The use of demerara sugar or fructose did not alter the acceptance of the products or the intensity of emotions. The use of brown sugar decreased acceptance (taste, texture, and overall impression) and the intensity of the emotions “active,” “loving,” “energetic,” “healthy,” and “refreshing.” The use of coconut sugar decreased acceptance (appearance, aroma, and taste) and the intensity of the emotions “refreshing” and “upset.” The use of honey improved acceptance in appearance and aroma but reduced the intensity of the emotions “active,” “loving,” “energetic,” and “healthy.” Based on sensory data, it is recommended to use demerara sugar or fructose as a substitute for sucrose. In conclusion, the study of emotions can be used as an additional tool for obtaining data related to the sensory acceptance of products.     

樱桃番茄果脯糖煮液废水的回用工艺及其对果脯品质的影响

目的:研究樱桃番茄果脯糖煮液废水的降黏回用工艺及其对果脯品质的影响.方法:对比6种降黏剂,以运动黏度和浊度为指标,确定降黏条件,并对比回用液的渗糖速率,建立废水降黏回用工艺.测定不同糖煮液腌渍果脯的营养成分、抗氧化能力和感官风味,评价回用工艺对樱桃番茄果脯品质的影响.结果:糖煮液废水经真空浓缩后回用,对果脯的脂溶性营养...