Mario Carlo Salvatore Agabbio

Changes of flavonoids, vitamin C and antioxidant capacity in minimally processed citrus segments and juices during storage

Abstract Citrus fruits of different species and cultivars, (“Red blush” grapefruit, “Palazzelli” mandarin-type fruit, “Minneola” tangelo and “Salustiana” and “Shamouti” orange) were minimally processed as segments or juices and cold-stored for up to 12 or 15 days, respectively. The flavanone glycosides, ascorbic acid (AA) content and antioxidant capacity were determined during storage. Minimal processing had almost no effect on the main chemical constituents, but ascorbic acid decreased significantly in “Minneola” and “Salustiana” segments, with values ranging from 1.63 to 5.10 mg per gram of dry matter, although only in the last samples taken. One of the three juices (Salustiana) also showed a decrease in AA content. The segments and juices showed different behaviour during storage with regard to the flavonoid content, which ranged from 0.77 mg to 8.32 mg/g dry matter in Palazzelli mandarin and Red blush grapefruit, respectively. A significant increase in total flavonoids (mainly hesperidin) was found in the segments, while the juices showed a diminution in flavonoid content . Antioxidant capacity increased significantly in “Red blush” grapefruit juices and “Salustiana” orange segments, decreased in “Salustiana” juices and “Minneola” tangelo segments and remained constant in the other samples. The antioxidant capacity, moreover, was clearly correlated ( r =0.968 and r =0.889 in segments and juices, respectively) with the ascorbic acid content rather than with the presence of flavanone glycosides.

Changes in ascorbic acid, polyphenol content and antioxidant activity in minimally processed cactus pear fruits

Abstract Cactus pear fruits ( Opuntia ficus indica Mill, cv. ‘Gialla’) were manually peeled, then placed in plastic boxes sealed with a film with high permeability to gases, and kept at 4°C for 9 days. After 3, 6 and 9 days, chemical, physical, microbiological and sensorial parameters, total phenols, vitamin C and antioxidant capacity were determined. In-package gas concentrations were measured almost daily. Vitamin C and antioxidant capacity remained unchanged, while polyphenols decreased after 6 days in storage. Of the chemical parameters, only pH and acidity changed significantly, without however, adversely affecting sensorial properties. Microbiological growth was limited and fungal colonies were never visually detected.

Influence of film wrapping and UV irradiation on cactus pear quality after storage

‘Gialla’ cultivar (cv) cactus pear fruit were either exposed or not to ultraviolet light (UV-C at 254 nm) and packaged or not with a polyolefinic film before cold storage for 1 month at 9°C plus 1 week of simulated shelf-life conditions at 20°C (SL). UV exposure did not affect fruit weight loss, while wrapping reduced significantly these losses to 1/4 after cold storage and 1/10 at the end of SL, with respect to unpackaged fruit. The overall visual rating of fruit appearance was higher in all the packaged fruit, while those unwrapped were affected by extended skin shrinkage both at the end of storage and SL periods. Skin damage, attributed to chilling injury and UV exposition, resulted higher in unwrapped fruits, in which the onset of these disorders was significantly reduced even when the fruit was UV subjected. Decay percentage was neither reduced by UV exposure nor by wrapping and reached values of about 10% at the end of the SL in all cases. Internal quality attributes and fruit taste were neither affected by wrapping nor by UV application. Wrapping the fruit with polyolefinic film had a beneficial effect in preserving fruit freshness and colour brightness, which were lost in unwrapped fruit.

Effect of Packaging and Coating on Fruit Quality Changes of Loquat During Three Cold Storage Regimes.

‘Palermitana’ loquat fruits ( Eriobotrya japonica Lindl.) were either coated with an edible coating or wrapped with an extensible PVC film. A third lot of fruits was used as control. Fruits were then cold stored at 2,4 and 8°C for 15 and 30 days plus 1 week of merchandising conditions at 20°C following each storage period. Upon removal, fruits were monitored for percent weight loss, overall appearance, chemical and physiological parameters (CO 2 and C 2 H 4 production) as well as rot incidence, flavour alterations and in-package concentrations of oxygen, carbon dioxide and ethylene. Wrapped loquats did not shrivel as packaging achieved a drastic reduction of weight loss, mainly in fruit stored at 2°C. Wrap was also beneficial in maintaining both the external appearance and the original flavour in both control and coated fruits. Coated fruits showed the highest weight loss and the worst appearance and taste. Chemical parameters and respiration rate were mainly affected by temperature. Carbon dioxide concentration within the package ranged from 0.3 to 1.2% and oxygen was about 20%, both in cold storage and in shelf-life periods. Our results show that film packaging could be a suitable tool for prolonging the storage life of loquat fruit.

5.14 – Minimal Processing of Fruit and Vegetables: Influence on Concentration and Activity of Some Naturally Occurring Antioxidants in Orange Derivatives

Nutritional factors are widely proved to be critical for human health. Overwhelming, evidence from epidemiological studies showed that diets rich in fruit and vegetables are associated with a reduced risk of degenerative diseases. This is attributed to the fact that these foods may provide an optimal mix of phytochemicals, such as antioxidants and their precursors. However, it is widely recognised that the health promoting capacity of fruit and vegetables strictly depends on their technological history. Processing is expected to affect content, activity and bio-availability of naturally occurring antioxidants. Although some experimental evidence has recently demonstrated that processing may have many effects, not always resulting in a loss of the health promoting capacity of fruit and vegetables, uncertainty still exists about the effective incidence of the various technological steps. This aspect, which is generally neglected or scarcely considered in present nutritional and epidemiological studies, is of great importance, considering that only a small amount of fruit and vegetables are consumed as fresh, whilst most of them need to be processed for safety, quality and economic reasons. Thus, investigation on the effects of processing on the activity of naturally occurring antioxidants is a key factor in order to find out the best technological conditions for preserving the above cited beneficial properties and to achieve a correct interpretation of data on dietary habits and human health. In the present investigation fresh and pasteurised orange juices, chosen by virtue of their high content in naturally occurring antioxidants and their widespread consumption, were considered. The changes in ascorbic acid concentration and in the overall antioxidant properties during juice preparation and storage, the latter carried out under different temperature conditions, were studied.

Effect of Prestorage High Temperature Conditioning on Fruit Quality, respiration and Ethylene Production of 'Hass' Avocado Fruit

Late-harvested ‘Hass’ avocado ( Persea americana Mill.) fruits were stored at 5°C for 0, 2, 4 or 6 weeks after being conditioned at 38°C for 0, 12, 24 or 36 hr. High temperature conditioning advanced the carbon dioxide peak in fruit exposed for 12 hr to high temperature and slightly lowered the magnitude of the climacteric in fruit heated for 36 hr. Ethylene evolution rate decreased as the time in storage and the exposure to high temperature increased. Heat treatment was detrimental in fruits exposed for 36 hr. These failed to ripen and showed severe heat injury, decay incidence and internal browning. In 24-hour heat-treated fruit, a significant delay in reaching the soft-ripe stage was obtained following removal to shelf-life ‘exposure’. Results of this study indicate that ‘Hass’ avocado fruit do not tolerate exposure at 38°C for longer than 24 hr, and that even shorter times of exposure may cause heat injury.