Influence of moderate heat pre-treatments on physical and chemical characteristics of kiwifruit slices (original) (raw)
Related papers
Effects of maturity stage and mild heat treatments on quality of minimally processed kiwifruit
Journal of Food Engineering, 2006
A central composite rotatable experimental design was used on kiwifruits of two distinct maturity stages (firm ripe and soft ripe), subjected to mild heat pre-treatments by immersion during 10-90 min in water at temperatures of 25-50°C. Minimal processing of the fruits was performed 24 h after the heat treatment and soluble solid content, colour and texture properties were analysed in the samples during the whole storage period (0-10 days). For both maturity stages, the effect of heat treatment on colour was negligible. For fruits of the early maturity stage (firm ripe), total content of soluble solids increased with the mild heat pre-treatments. Pretreatments avoided texture breakdown in firm ripe kiwi slices. Firmness, the most sensitive parameter, is increased or preserved using treatment periods of up to 40 min. Favourable responses were evidenced immediately after them and during the whole storage period. Therefore, mild heat pre-treatments, when applied to firm ripe kiwi at temperatures below 45°C during less than 25 min improve the quality, mainly the firmness, colour being only marginally affected.
Food Chemistry, 2008
The effect of moderate heat treatment combined with calcium dips on the quality of minimally processed kiwifruit was studied. Whole fruits were treated for 25 min at 45°C by dipping in deionised water or CaCl 2 solutions (1%, 2% and 3% (w/v)) and cooled to 4°C. Twenty-four hours later fruits were peeled, sanitized, cut into slices and packed. The firmness of kiwifruit slices' was subsequently evaluated during 8 days of storage. Calcium content, pectinmethylesterase activity and heat shock proteins accumulation were also investigated. Heat treatment conducted in water induced a firming effect and avoid softening of fruit slices while calcium dips had a marginal effect on this parameter. A calcium loss was observed due to dip treatment, but this effect was minimized when treatment was conducted in 3% CaCl 2 solution. The firming effect provided is due to the activation of pectinmethylesterase and the presence of calcium in treatment solution reduces or inhibits enzyme activation. Under the tested conditions, no heat shock proteins de novo synthesis was detected.
Food and Bioprocess Technology, 2013
The effect of heat pre-treatment (45°C/25 min), applied to whole fruit, and post-cut calcium dips in 1 and 2 g/L CaCl 2 solutions on respiration rate and texture preservation of kiwifruit slices was studied. During a 9-day period, packages' atmosphere composition, slices' firmness, pectin content and sensory scores were evaluated. Histological observations of samples were also performed. Neither heat pre-treatment nor calcium dips alone were effective in diminishing respiration rate of the slices but the application of both treatments revealed a synergistic effect on respiration rate reduction. Calcium-dipped fruit slices showed better firmness preservation. Post-cut calcium dips, alone or combined with heat pre-treatments, yielded slices presenting higher insoluble/total galacturonic acid ratio, indicating formation of calcium pectates. Slices from heat-pre-treated fruits, even in the absence of calcium, also revealed insoluble/total galacturonic acid ratio similar to calciumtreated slices, supporting, despite the lower firmness value, a more structured tissue, as observed in SEM microphotographs. Sensory and physical-chemical parameters obtained were correlated. The effectiveness of calcium treatment was equally observed for both tested concentrations during a 9-day shelf life period.
LWT - Food Science and Technology, 2009
The effects of air-drying temperature on the cell wall components of three sets of fresh kiwifruits at different degrees of ripening, unripe, half-ripe and ripe samples, have been evaluated. The modifications affecting the physico-chemical properties of cell wall polysaccharides were largely dependent, not only on the air-drying temperature used (from 30 C to 90 C), but also on the initial stage of ripening of the processed kiwifruits. Thus, whereas in comparison with the fresh fruits, dehydrated unripe and half-ripe kiwifruits maintained their overall cell wall composition better, processed ripe kiwifruits seemed to be more sensitive to cell wall degradation/solubilisation. In fact, important losses of cell wall material (CWM), mainly pectins and, also, hemicelluloses, were detected in the riper kiwifruits when these samples were dehydrated at high temperature (up to 30% CWM losses when drying was carried out at 90 C). Heating also promoted considerable modifications of the degree of methyl-esterification (DME) of pectins. In general, an increase in the DME corresponded to an increase in the degree of ripening of the processed samples, suggesting that methylated pectins exhibited a higher resistance to the degradation/ solubilisation caused by heating. All these changes in composition were clearly reflected in the solubility and functional properties (FP) of processed CWMs. Hydration properties, swelling and water retention, and, in particular, the capacity to absorb lipids, were modified after processing. In general, CWMs from processed half-ripe kiwifruits exhibited the highest FP values. Overall, the study clearly reflects the importance of taking into consideration the stage of ripening of fruits in order to determine the final quality of CWMs, and therefore, the properties of the dietary fibre (DF) which could be obtained from processed kiwifruit samples.
Fruit Growing Research
Kiwifruit is recognized as highly nutritious having many biochemical characteristics that deliver a range of health benefits. In Romania, kiwi is a new fruit species and the creation, testing and introduction of winter hardy genotypes, adapted to the local harsh climate conditions is a priority. A common Italian-Romanian kiwifruit breeding program was initiated in 1993 and during the time, several hybrid genotypes were obtained and introduced to be tested. After more than two decades of research, it was demonstrated that Actinidia deliciosa and Actinidia chinensis can be grown in Romania in peach favourable areas, while Actinidia arguta (hardy kiwi, kiwiberry) can cover larger areas, suitable for plum cultivation. At the Faculty of Horticulture within the University of Agronomic Sciences and Veterinary Medicine of Bucharest, an experimental field with kiwifruit hybrid genotypes, was established in 1993. The plants were grown under an organic orchard management, on a T-bar trellis, being irrigated with micro sprayers. The fruits were harvested at beginning of November, in 2017 and 2018. Harvesting moment was established when the fruit flesh firmness was lower than 7.0 kg force cm 2. After harvesting, kiwifruits were stored in two different cold storage conditions: normal atmosphere (NA) at 3°C and 95% humidity and controlled atmosphere (CA) with 1.5% Oxygen, at 1-2°C and 95% humidity. The aim of this study was to analyse the fruit quality characteristics of some new kiwi hybrid genotypes at harvest and during storage with the final goal to select best elites. Fruit weight and shape index have been determined after harvest. Different fruit characteristics were measured and evaluated in dynamics: firmness, soluble solids, dry matter, titratable acidity and ascorbic acid. All the determinations and analyses were made at the Research Center for Studies of Food Quality and Agricultural Products laboratories. During the storage, observations showed that R1P9 kiwifruit hybrid presented better biochemical quality parameters and the lowest weight losses compared to the other studied hybrids-4.69 % in CA and 5.22 % in NA. As expected, keeping kiwi fruits in controlled atmosphere with 1.5% Oxygen, at 1-2°C and 95% humidity, presented better physical and biochemical quality compared with those stored in normal atmosphere, at 3°C and 95% humidity. Using the results of the study regarding the fruits physicochemical characteristics after harvesting and during the storage, but also some other plant parameters, several kiwi hybrid elites were selected-R0P13 and R1P9. They will be propagated and planted for the production test. Cuvinte cheie: fermitate pulpă, substanţă uscată solubilă, substanţă uscată totală, aciditate titrabilă, acid ascorbic.
Journal of Agricultural and Food Chemistry, 2010
Consumption of minimally processed fruit and vegetables has increased significantly in the past few years due to the consumers' life style. The aim of this study was to evaluate the effect of treatment with ascorbic acid or calcium chloride on the quality parameters of fresh-cut kiwifruit prepared from fruit previously stored for 3 months, either treated or not treated with 1-methylcyclopropene (1-MCP) before storage. Harvested fruit were treated with 1 μL L-1 1-MCP for 20 h at room temperature (∼20°C) (MCP) or had no treatment (C) and were then stored at 0°C. After 3 months, fruit were removed from storage, peeled, and cut longitudinally in quarters, dipped in 2% ascorbic acid (Asc), 2% calcium chloride (Ca), or just water (cont), and kept at 2°C for 8 days. Measurements of firmness, soluble solids content (SSC) (°Brix), color (CIE L*, a*, b*), electrolyte leakage, sugars, organic acids, total phenolics, and antioxidant activity (DPPH and ABTS) were performed at 0, 4, and 8 days. A taste panel was performed on the seventh shelf life day. It was shown that whole MCP-treated kiwifruit kept better than the control through the 3 months storage, this effect being lost through the fresh-cut shelf life period. Furthermore, the postcut dip on 2% CaCl 2 was effective on delaying softening and browning of fresh-cut kiwifruit, which were also the fruit preferred by panelists. Both ascorbic acid and CaCl 2 were effective on preserving or improving nutritional properties (phenolics, ascorbic acid, DPPH, and ABTS) mainly in the first 4 days of shelf life. The CaCl 2 had a further beneficial effect until 8 shelf life days. It is suggested that CaCl 2 is better in keeping overall quality through 8 days of shelf life at 2°C in fresh-cut kiwifruit followed by Asc, and 1-MCP has negligible effect in the conditions of this experiment.
Applied Sciences, 2020
Undersized kiwifruits are considered waste; therefore, there is a need to develop sustainable processing technologies for their valorization, in order to have a positive economic impact on their entire production chain. Therefore, the aim of this study was to apply pulsed electric fields (PEF) combined with osmotic dehydration (OD) and air drying (AD) to develop a novel yellow kiwifruit dried snack with high nutritional functionality. In particular, the effect of the different pre-treatments, PEF (200 V/cm) and/or OD (trehalose at 40%), on the color, bioactive compounds content and antioxidant activity (AA) was evaluated on kiwifruit chips air-dried at three different temperatures (50, 60, 70 °C). The results showed that better color maintenance was observed at the drying temperature of 60 °C. Concerning the bioactive compounds, a good retention in total polyphenols (TP), vitamin C content and AA with the DPPH method was obtained on OD and PEF kiwifruit dried snacks, similar to that...
Effect of kiwiberry pre-storage treatments on the fruit quality during cold storage
Zemdirbyste-Agriculture
The kiwiberry (Actinidia arguta (Siebold et Zucc.) Planch ex Miq) has become a widely studied species in recent years due to its high resistance to low temperature and high content of health-promoting phytochemicals. The aim of this study was to verify the effect of pre-storage application of oxalic acid, salicylic acid and acetylsalicylic acid, calcium chloride (CaCl 2 ) and 1-methlycyclopropene (1-MCP) on quality changes of the kiwiberry cultivar 'Weiki' during cold storage. During six weeks of storage fruit firmness, titratable acidity and the total ascorbate content decreased from an average of 61 N, 1.5%, 857 mg kg -1 to 2.5 N, 1%, 380 mg kg -1 , respectively. Contrary, the soluble solids and the total phenolics content increased from an average of 0.30%, 73.5 mg kg -1 to 0.51%, 172 mg kg -1 , respectively. Application of 1-MCP clearly improved fruit firmness and inhibited the ascorbate loss. Compared to the control, the fruit firmness and total ascorbate content was higher by 50% and 13%, respectively. The acetylsalicylic acid treated fruit exhibited significant drop of phenolics as compared to the control. There was no significant difference in fruit total antioxidant activity determined immediately after harvest and at the end of storage (16.7 vs 17 mmol kg -1 , respectively). Fruit treated by salicylic acid, CaCl 2 and 1-MCP was characterized by a significantly higher titratable acidity compared to the control group. This study showed that the highest ability to maintain fruit quality during cold storage was exhibited by 1-MCP treated kiwiberry.
African Journal of Biotechnology, 2011
This study was carried out to determine some chemical and physical properties at physiological maturity and ripening period of kiwifruit. The average geometric mean diameter, sphericity, bulk density, porosity, projected area along three axes (X, Y, Z) and colour characteristics (L*, a*, b*) were measured at physiological maturity and ripening period. Total soluble solid content, titratable acidity, pH, total phenolic, total antioxidant activity and total sugar of kiwifruit were also determined. The total antioxidant value was higher at physiological maturity than ripening period.