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This research focuses on the effect of maturity stage and storage conditions on quality and consumer satisfaction of ‘Big Top ® ’ nectarines. At harvest time, fruit were graded in three categories according to the I AD index (index of absorbance difference = A 670 − A 720 ) based on Vis spectroscopy. Physicochemical parameters (soluble solids concentration, titratable acidity and flesh firmness) were measured for the three maturity categories at harvest time and after up to 49 days of storage at 20, 10, 4 or −1 °C. Consumer satisfaction and sensory attributes were also measured on fruit from all three categories at harvest time, as well as on fruit from the intermediate maturity class after storage at the different tested temperatures for up to 49 days. At harvest time, consumer's satisfaction increased significantly with maturity stage at harvest, mainly due to an upper sweetness and flavour perception and higher SSC value detected in the most mature class. For short storage periods, ‘Big Top ® ’ nectarines kept at 20 °C received the highest scores for peach flavour intensity and overall acceptance. For longer storage periods, no significant differences among temperatures were observed on sensory quality or consumer satisfaction, except for fruit stored for the longest period (7 weeks), for which higher consumer acceptance was found for fruit stored at −1 °C than at 4 °C. Results also suggested that higher acceptance scores were associated mainly to more intense perception of flavour. [ABSTRACT FROM AUTHOR]

Abstract: The effect of strain on fruit color development and anthocyanin content, fruit quality, volatile compound emissions and consumer acceptability was evaluated on seven ‘Fuji’ apple strains (Malus domestica Borkh.) at the IRTA (Spain) over a period starting three weeks commercial harvest in 2008 and ending one week after harvest. Based on fruit color, measured with a portable tristimulus colorimeter, and anthocyanin content, the most colored strain was ‘Zhen Fuji Aztec’ (blushed), followed by ‘Fuji 6629’ (also blushed), ‘Fuji Kiku 8’ and ‘Rubin Fuji’ (both striped). ‘Fuji Chofu 2’ (blushed) and ‘Fuji Suprema’ (barely striped) were the least colored strains, although fruit color started earlier in the last one. ‘Ogura’ (barely striped) provided intermediate values. The most important increase in anthocyanin content and decrease in hue values was recorded from one week before commercial harvest until harvest, in all strains except ‘Fuji Suprema’. Highly colored strains developed a red color on both sides of the fruit with greater average values for strains with greater colored surfaces than for less colored strains. A medium relationship between hue angle, L* and a*/b* ratio and anthocyanin content was established. Fruit quality parameters for the different harvest dates as fruit firmness, soluble solid content (SSC), titratable acidity (TA), and starch index were similar for the different cultivars and date. Fruit firmness is well maintained across different dates even with high values of starch index. Differences in fruit color, intensity and type, were not related to differences in the fruit quality parameters of the different strains. Ripening time was therefore not related to the intensity or type of fruit color. There are some quantitatively and qualitatively differences among the volatile profiles of all the ‘Fuji’ strains. In quantitative terms, the ‘Fuji’ strain that emitted the lowest total concentration was ‘Fuji Aztec’. There were no statistical differences among the total volatile compound concentrations of ‘Fuji Kiku 8’, ‘Rubin Fuji’, ‘Fuji 6629’ and ‘Fuji Chofu 2’, which obtained the highest values. The main volatile compound emitted for all of the analyzed strains was the 2-methylbutyl acetate. In general, apples of the most colored strains emitted less volatile compound compared to the least colored. Concerning to consumer acceptability, ‘Fuji Aztec’ strain got the lowest mean score, but there were no differences among the rest of ‘Fuji’ strains. A full-data principal component analysis was run. This analysis showed a high correlation between consumer acceptability and some of the volatile compounds emitted, in addition to fruit that exhibit bigger hue angles on the exposed side (lower red color). [Copyright &y& Elsevier]

Abstract: The influence of nectarine cultivar and the harvest date on fruit colour, fruit size, fruit quality parameters, and consumer acceptance were assessed. The analyses were carried on cultivars with different fruit taste (acidity and sweetness), from 5-years-old trees at the IRTA-Experimental Station of Lleida (Spain). The six cultivars were grouped in three pairs in which each had a similar commercial harvest date. Each pair comprised by a non-acid cultivar and an acid cultivar, except the pair of ‘Big Top®’ and ‘Mesembrine®’, which included two non-acid cultivars. The nectarines were harvested at 8 days intervals on five harvest dates, three of which were before the commercial harvest date, one at commercial harvest and another 1 week after commercial harvest. On all of the harvest dates the non-acid cultivars always presented a more intensity of red skin colour than the acid cultivars, and they developed red colouration earlier. Compared to non-acid, acid cultivars showed also a greater differences in red colour between the exposed side and the shade side of the fruit. The evolution of fruit weight and of soluble solids content over the different harvest dates was similar for both groups of cultivars. Acid cultivars showed a significantly faster decrease in fruit firmness, especially evident in the case of early season cultivars as ‘Alicecov’. The sugar-to-acid ratio of the non-acid nectarines was 2–3 times higher than with the acid cultivars. The consumer acceptance was always greater for non-acid than for acid cultivars, even at early or advanced stages of fruit maturity. [Copyright &y& Elsevier]

Abstract: The effect of strain on fruit colour development, chromaticity values and anthocyanin content, fruit quality and consumer acceptance was evaluated on eight ‘Gala’ apple strains (Malus domestica Borkh.) at the IRTA (Spain), during a period from 4 weeks before to 1 week after commercial harvest. Based on fruit colour, measured with a Minolta CR-200 portable tristimulus colorimeter, and anthocyanin content, the most coloured strains were ‘Royal Beaut’, ‘Buckeye Gala’ (both semistriped) and ‘Ruby Gala’ (blushed). ‘Brookfield’ and ‘Schniga’ (both striped) provided an intermediate level of colour, while ‘Galaxy’ and ‘Mondial Gala’ (both striped) were the least coloured ones. The most important increase in colour development was recorded from 2 weeks before the commercial harvest and continued also increasing after harvest. Highly coloured strains developed a red colour on both fruit sides with greater average of fruit surface coloured, while the less coloured strains exhibited different colouration between sides, more bicolour fruits and lower average of fruit coloured. Fruit size and yield were, in general, the same for all strains. Instrumental fruit quality parameters along the different harvest date: fruit firmness, soluble solids content (SSC), titratable acidity (TA), and starch index were similar for the different cultivars. Differences in fruit colour/anthocyanin content were not related to differences in fruit quality parameters of different strains. Thus, ripening time was not related to the degree of fruit colour. Principal component analysis of the samples characterized by all the variables showed a chronological distribution along the first principal component PC1, indicating different maturity stages. Internal preference mapping showed three consumer clusters and indicated that the largest number of consumers preferred samples harvested at commercial harvest or 2 weeks before this date. We also observed a clear influence of maturity stage on consumer acceptance but there was no clear influence with respect to strain. [Copyright &y& Elsevier]

Standard quality parameters, consumer acceptability, emission of volatile compounds and ethylene production of ‘Mondial Gala®’ apples (Malus × domestica Borkh.) were determined in relation to storage atmosphere, storage period and shelf-life period. Fruit were harvested at the commercial date and stored in AIR (21kPa O2:0.03kPa CO2) or under three different controlled atmospheres (CAs): LO (2kPa O2:2kPa CO2), ULO1 (1kPa O2:1kPa CO2), or ULO2 (1kPa O2:2kPa CO2). Fruit samples were analysed after 12 and 26 weeks of storage plus 1 or 7d at 20°C. Apples stored in CA maintained better standard quality parameters than AIR-stored fruit. The volatile compounds that contributed most to the characteristic aroma of ‘Mondial Gala®’ apples after storage were butyl, hexyl and 2-methylbutyl acetate, hexyl propanoate, ethyl butanoate, ethyl hexanoate, ethyl, butyl and hexyl 2-methylbutanoate. Data obtained from fruit analysis were subjected to principal component analysis (PCA). The apples most accepted by consumers showed the highest emission of ethyl 2-methylbutanoate, ethyl hexanoate, tert-butyl propanoate and ethyl acetate, in addition to the highest titratable acidity and firmness values. [Copyright &y& Elsevier]

‘Fuji’ apples were harvested at two different dates, over two consecutive years (1999 and 2000), and stored under different atmosphere conditions: AIR (21 kPa O2+0.03 kPa CO2), SCA (3 kPa O2+2 kPa CO2) or ULO (1 kPa O2+2 kPa CO2). After 3, 5 or 7 months of storage plus 1 or 10 days of ripening at 20 °C, aroma volatile emission and quality parameters were measured. Generally, the highest total aroma emission was obtained after 5-months storage and 1 day of ripening at 20 °C regardless of atmosphere conditions, for early-harvested fruit. After 7-months storage, the ULO atmosphere depressed total aroma volatile emission. The compounds contributing mostly to the characteristic aroma of ‘Fuji’ apples were ethyl 2-methylbutanoate, 2-methylbutyl acetate and hexyl acetate, and their concentrations were higher the first day after removal from storage at 5, 3 and 7 months, respectively. Storage conditions and season had a significant effect on aroma volatile compounds. [Copyright &y& Elsevier]

Production of volatile aroma compounds, and quality parameters, were monitored in relation to the activity of lipoxygenase, pyruvate decarboxylase, alcohol dehydrogenase and alcohol o-acyltransferase during maturation of ‘Fuji’ apples. Acetate esters increased during maturation and were quantitatively the most significant compounds contributing to ‘Fuji’ aroma. Increase in acetate ester production was associated with the availability of the necessary alcohol precursors. Principal component analysis revealed a clear separation according to sampling date, which accounted for up to 67% of total variance, and allowed ‘Fuji’ apples used in this study to be classified into three ripeness stages. Overall the results suggest that precursor availability for the related enzymes is a more significant factor than enzyme activity for the development of aroma during on-tree maturation of ‘Fuji’ apples. [Copyright &y& Elsevier]

Abstract: ‘Big Top’ and ‘Venus’ nectarines and ‘Early Rich’ and ‘Sweet Dream’ peaches were picked at commercial maturity and stored for 20 and 40d at −0.5°C and 92% RH under either air or one of the three different controlled atmosphere regimes (2kPa O2/5kPa CO2, 3kPa O2/10kPa CO2 and 6kPa O2/17kPa CO2). Physicochemical parameters and volatile compounds emission were instrumentally measured after cold storage plus 0 or 3d at 20°C. Eight sensory attributes were assessed after cold storage plus 3d at 20°C by a panel of 9 trained judges, in order to determine the relationship between sensory and instrumental parameters and the influence of storage period and cold storage atmosphere composition on this relationship. A principal component analysis (PCA) was undertaken to characterize the samples according to their sensory attributes. PCA results reflected the main characteristics of the cultivars: ‘Big Top’ was the nectarine cultivar with the highest values for sweetness, juiciness and flavor; ‘Sweet Dream’ was the sweetest peach and was characterized by high values for crispness and firmness, while ‘Venus’ and ‘Early Rich’ were characterized by their sourness. To assess the influence of storage period and CA composition on sensory properties, a PLS model of the flavor of the different samples was constructed using standard quality attributes and volatile concentrations as the X-variables. The model with 2 factors accounted for more than 80% of flavor variance. PLS results indicated that the main influence on flavor perception was storage period. Atmosphere composition also had an influence on flavor perception: flavor perception decreased from samples stored in a 2/5 O2/CO2 atmosphere composition to those of 3/10 and 6/17. These results can be qualitatively extended to juiciness and sweetness since all these sensory properties were strongly correlated. [Copyright &y& Elsevier]

‘Pink Lady®’ apples were harvested at commercial maturity, treated with three different agrochemical products, and stored at 1°C under either air or controlled atmosphere conditions (2kPa O2 +2kPa CO2 and 1kPa O2 +1kPa CO2) for 13 and 27 weeks, followed by 4 weeks storage in air at 1°C. Diphenylamine, folpet and imazalil contents in both the skin and flesh were simultaneously determined after cold storage plus simulated marketing periods of 1 and 7d at 20°C. After 27 weeks plus 7d, diphenylamine and folpet levels in apple skin were lower for fruit stored in low O2 (2kPa) or air than for those kept under ultra-low O2 (1kPa). An additional storage period of 4 weeks in air reduced diphenylamine and folpet contents in whole apples stored for 13 weeks in the low O2 controlled atmosphere. For imazalil, the same result was obtained in apple skins stored for 27 weeks under an ultra-low O2 controlled atmosphere. Differences in diphenylamine and folpet contents were found for skin and flesh samples throughout the simulated marketing period, but there were observable differences in imazalil contents only for flesh samples. [Copyright &y& Elsevier]

The production of aroma volatile compounds and standard quality attributes, in addition to lipoxygenase (LOX), hydroperoxide lyase (HPL), pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH) and alcohol o-acyltransferase (AAT) activities, were assessed during maturation of ‘Pink Lady®’ apples. Low production of aroma volatiles was observed in early harvested fruit, which gradually increased as ripeness approached. Hexyl acetate, hexyl 2-methylbutanoate, hexyl hexanoate, hexyl butanoate, 2-methylbutyl acetate and butyl acetate were prominent within the blend of volatiles produced by fruit throughout maturation. Multivariate analysis showed these compounds had the highest influence on differentiation of maturity stages, indicating that aroma volatile emission is an important factor for definition of fruit ripeness, which suggests production of these esters might be useful as an index of maturity. No large variations in AAT activity were found throughout the experimental period despite increasing ester emission, suggesting the enhancement of ester production by ‘Pink Lady®’ apples at ripening arises mainly from greater availability of substrates. Increased LOX activity was observed at later stages of fruit development, and the possible role of this enzyme activity on enhanced capacity for aroma volatile biosynthesis in more mature fruit is discussed. [Copyright &y& Elsevier]

We developed a simple microtechnique to measure lipids in milk by UV spectrophotometry. This technique is based upon the property of fatty acids to absorb UV light proportional to their concentration. Samples of powdered or fluid milk (30 or 60 µL) were added to 3 mL of analytic grade ethanol and stored at -20°C for at least 1 h. This procedure precipitates proteins and hydrophobic peptides that interfere with UV measurement. Sample absorbances are then measured at 208 nm in an UV-Vis spectrophotometer. This technique correlated very well against Milko-Scan, a device that measures milk fat by IR spectroscopy, with an r² > 0.982. Accuracy and precision, evaluated by recovery and replicate assays, are also very acceptable. This method is suitable as a fast, cost-effective alternative screening method to estimate milk fat content in small samples without prior lipid extraction. [ABSTRACT FROM AUTHOR]

Abstract: Pre-storage at 20°C before cold storage was used to improve volatile compound emissions of ‘Big Top’ nectarine and ‘Early Rich’ peach fruit without negatively affecting quality measures and sensory attributes. Commercially harvested fruit were subjected to pre-storage at 20°C for 0, 10, 24, or 36h and then stored at −0.5°C for 10, 20, or 40 d. After cold storage, the fruit were kept at 20°C for up to three days. ‘Big Top’ nectarines given 10h pre-storage followed by 10 and 20 d cold storage were perceived as more flavourful, juicy, and sweet, had higher soluble solid contents, and contained more butyl propanoate, 2-methybutyl-2-methylpropanoate, and 2-methyl-1-butanol than control fruit. ‘Early Rich’ peaches given 36h pre-storage followed by 20 d cold storage were perceived as sweeter and had more propyl acetate, pentyl acetate, and 2-methyl-1-butanol than control fruit. [Copyright &y& Elsevier]

Abstract: Standard quality parameters, consumer acceptance, and volatile compound emission of ‘Pink Lady®’ apples (Malus × domestica Borkh.) were measured at harvest and after 14 and 25 weeks of cold storage in three different atmospheres. After storage, fruit were left to ripen for 1 and 7 days at 20°C before instrumental and sensory measurements were performed. Data were subjected to principal component analysis (PCA) and partial least square regression (PLSR). PLSR results indicated that the parameters positively influencing acceptability were soluble solid content, titratable acidity, background colour, and emission of hexyl 2-methylbutanoate, hexyl hexanoate, hexyl propanoate, butyl 2-methylbutanoate, 2-methylbutyl acetate and butyl propanoate. Results of sensory analyses revealed the treatments considered in this work could be split into two levels of acceptability. [Copyright &y& Elsevier]

Abstract: Emission of aroma volatile compounds and some related enzyme activities (LOX, PDC, ADH, and AAT) were assessed in ‘Fuji’ apples (Malus × domestica Borkh.) during shelf life at 20°C following cold storage under air or under three different CA conditions (3kPa O2:2kPa CO2; 1kPa O2:1kPa CO2; or 1kPa O2:2kPa CO2). Data were used for principal component analysis (PCA) and partial least-square regression (PLSR) analysis of results. LOX activity was partly inhibited by hypoxic conditions, and thus could have contributed to differentiation between air- and CA-stored fruit. Accordingly, emission of straight-chain esters was also higher in air- than in CA-stored fruit. In contrast, PDC activity was responsible for part of the differences between low (3kPa) and ultra-low (1kPa) O2 storage conditions, probably by providing substrates for AAT action. AAT activity afforded no satisfactory differentiation between samples, and therefore it is suggested that substrate availability is a more decisive factor than enzyme activity for volatile production after storage. The PCA and PLSR models developed in this work were not useful for discrimination between the two studied ultra-low O2 conditions. [Copyright &y& Elsevier]