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Combined processes based on acidification ( pH: 4.5, 5.0, 5.5) and mild thermal treatments ( T: 56, 58, 60°C) at different exposure times ( t: 2, 4, 6 min) were optimised using the response surface methodology to improve the functional quality of carrot juice. The effects on α- and β-carotenes, total antioxidant activity ( TAA) and colour parameters were assessed. All combinations exhibited higher α- and β-carotenes than untreated juice due to an increase on the extractability during processing. T was the most influential factor increasing carotenes as T increased. Conversely, TAA was more affected by pH. The maximum TAA was observed at pH 4.5 at 56°C. Moreover, samples with the lowest pH were the most luminous with highest a* and b*. The combination of pH 4.5 at 60°C, 4 min simultaneously showed high carotenes and TAA, resulting a good alternative to improve the functional quality and colour of carrot juice. [ABSTRACT FROM AUTHOR]

The impact of heat treatment using hot air (HT 45 °C and 55 °C for 1 h) and two active modified atmosphere packaging (MAP) conditions of high oxygen atmosphere (HOA: 80 kPa O2, 20 kPa N2) and high CO2 atmosphere (HCA: 20 kPa CO2, 80 kPa N2), individually or combined, on the antioxidant capacity, polyphenols, vitamin C content, total anthocyanins, polyphenoloxydase (PPO) activity and shelf life of fresh-cut (FC) pomegranate arils stored for 14 days at 4 °C was studied. The results indicate that HT 45 °C along with HOA inhibited PPO activity and prevented loss of antioxidant capacity, vitamin C and phenolic compounds in arils, in comparison with control and HT 55 °C. All treatments reduced the accumulation of anthocyanins, but HCA-treated arils lost more anthocyanins besides having worse a* colour parameter values. No significant differences in titrable acidity (TA) and total soluble solids (TSS) were observed between treatments. The combination of HOA and HT 45 °C enhanced the benefits of applying each treatment separately and could be useful to improve and extend postharvest life of pomegranate FC arils. [ABSTRACT FROM AUTHOR]

Nectarine [ Prunus persica (L.) Batsch] is a sought-after fruit due to its properties. In addition, minimally processed produces are more and more accepted by consumers. Four nectarine cultivars ('Early Top', 'Nectaprima', 'Big Top' and 'Venus') were selected to study their suitability for minimal processing. Samples were processed in a clean room at 8 °C, washed them in water (4 °C) and stored at 4 °C in modified atmosphere packaging. The samples were analysed at 0, 3, 6 and 9 days of storage, and quality parameters as well as functional compounds (polyphenols and polyphenol oxidase activity) were studied. Principal component analysis ( PCA) was carried out to assess the relationship between nectarine cultivars and determined parameters. In conclusion, 'Early Top' and 'Nectaprima' cultivars showed the best quality results and therefore a promising suitability for fresh-cut processing. Nevertheless, the remaining cultivars should not be ruled out due to their functional content, advising additional conservation treatments for them. [ABSTRACT FROM AUTHOR]

The aim of the study was to quantify and model the retention of total anthocyanins ( TAR), ascorbic acid ( AAR) and total vitamin C (Vit C), and the colour changes of fresh-cut strawberries after washing disinfection with peracetic acid ( PAA) at different concentrations (0-100 mg L−1), times (10-120 s) and temperatures (4-40 °C). Two strawberry cultivars ( Camarosa and Selva) were used. TAR (%) and AAR (%) were principally affected by PAA concentration and processing time in both cultivars. There was an approximately 90% Vit C retention at any condition in the experimental domain for Camarosa cultivar. However, in the case of Selva cultivar, total vitamin C retention and colour changes were affected by the processing variables. [ABSTRACT FROM AUTHOR]

Lettuce as a component of processed salad packs often suffers from pinking or browning discoloration on leaf surfaces within a few days after harvest limiting product shelf life. A lettuce diversity set representing the primary gene pool was used to investigate phenotypic variation for postharvest discoloration. Discoloration of minimally processed lettuce was assessed using material harvested from a replicated field trial. Significant variation for pinking and browning was recorded ( P < 0.001). Rates of discoloration were specific to lettuce type, however potential for pinking or browning within a type varied. Interestingly, accessions were significantly more susceptible to browning ( P < 0.05) early postharvest (day 1) but significantly more susceptible to pinking ( P < 0.05) during later stages (days 6, 9 and 13). The results indicate that there is a genetic basis for this phenotypic variation and this natural allelic variation could be exploited through breeding to develop discoloration resistant cultivars, consequently minimising pre- and postharvest treatments and reducing food wastage. [ABSTRACT FROM AUTHOR]

Litchi ( Litchi chinensis Sonn.) fruits are very susceptible to pericarp browning which adversely affects consumer acceptability even though the aril portion remains in excellent condition. Litchi arils (litchis) were treated with a solution containing 0–2% (w/v) calcium lactate (CL), 0–0.02% (w/v) 4-hexyl resorcinol (4-HR) and 1% potassium sorbate. The pH of solution was adjusted to 4.0 with citric acid. Treated litchis were packed in polystyrene trays, over-wrapped with polypropylene film, vacuum-packed (0, 47409.3, 94831.9 Pa) and stored at 4 ± 2 °C. Drip losses, pH, total soluble solids (TSS), sensory attributes and microbiological quality of stored samples were estimated. A four-factor, three-level experimental design (D6 Hokes design) with 19 experiments was chosen. Mathematical models were developed to analyse and predict the effect of CL, 4-HR, in-package vacuum and storage time on the responses. TSS, pH and sensory scores decreased significantly ( P ⩽ 0.01), whereas drip losses and microbial count increased significantly ( P ⩽ 0.01) with time. Drip loss was significantly ( P ⩽ 0.1) reduced by addition of CL. 4-HR prevented browning and changes in colour score during storage were significantly less. Vacuum in packages exerted significant ( P ⩽ 0.01) effect over pH, TSS, sensory and microbiological qualities of minimally processed litchis. [ABSTRACT FROM AUTHOR]

The effect of modified atmospheres, generated by using different packaging films, on the quality of sliced mushrooms was evaluated. The carbon dioxide and oxygen content inside the packages as well as the colour, texture, weight loss, sensory attributes, mesophiles, psychrotrophs, Pseudomonas fluorescens, faecal coliforms, Escherichia coli and anaerobic spores were determined. Modified atmospheres containing 2.5% CO2 and 10–20% O2 reduced the microbial counts and improved the mushrooms’ appearance when compared with an air atmosphere. Modified atmospheres containing 15% CO2 and <0.1% O2 inhibited mushroom development and toughening and reduced microbial growth. Although these atmospheres had no effect on colour, they did allow the development of off odours and anaerobic spores were detected. No differences in microbial growth or mushroom spoilage were observed under the different moisture contents generated in the packages at 4 °C. Aerobic bacteria counts were considered very high even at the beginning. [ABSTRACT FROM AUTHOR]

The sensory shelf-life of Golden Delicious fresh-cut apples, dipped in 10 g L−1 ascorbic acid and 5 g L−1 calcium chloride and packaged under different modified atmosphere conditions, was assessed throughout refrigerated storage. An initial atmosphere of 0 kPa O2 and plastic packages of an O2 permeability of 15 cm3 m−2 bar−1 day−1 were very effective in preserving the initial colour and firmness of apple cubes during at least 3 weeks of storage. These conditions resulted in increased respiration coefficients, which curbed the product consumer acceptance beyond the second week of storage. However, reduced ethylene and CO2 production limited the appearance of fermentative metabolites during this period. [ABSTRACT FROM AUTHOR]