Alessandra Del Caro

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.

Distinctive Anthocyanin Accumulation Responses to Temperature and Natural UV Radiation of Two Field-Grown Vitis vinifera L. Cultivars

The responses of two red grape varieties, Bovale Grande (syn. Carignan) and Cannonau (syn. Grenache), to temperature and natural UV radiation were studied in a three-years field experiment conducted in Sardinia (Italy), under Mediterranean climate conditions. Vines were covered with plastic films with different transmittances to UV radiation and compared to uncovered controls. Light intensity and spectral composition at the fruit zone were monitored and berry skin temperature was recorded from veraison. Total skin anthocyanin content (TSA) and composition indicated positive but inconsistent effects of natural UV light. Elevated temperatures induced alterations to a greater extent, decreasing TSA and increasing the degree of derivatives acylation. In Cannonau total soluble solids increases were not followed by increasing TSA as in Bovale Grande, due to both lower phenolic potential and higher sensitivity to permanence of high temperatures. Multi linear regression analysis tested the effects of different ranges of temperature as source of variation on anthocyanin accumulation patterns. To estimate the thermal time for anthocyanin accumulation, the use of normal heat hours model had benefit from the addition of predictor variables that take into account the permanence of high (>35 °C) and low (<15 °C and <17 °C) temperatures during ripening.

Improving Baking Quality of Weak Gluten Semolina Using Ovine Whey Powder

The effect of the addition of ovine whey powder at 5%, 10%, and 15% on bread quality was studied. Two different types of semolina were used, one being a commercial blend with strong and tenacious gluten (48T) and the other coming from one single cultivar, characterized for having weak and sticky gluten (4T). Two different types of typical Mediterranean bread were produced, pan bread and flat bread, and their quality characteristics were measured, together with their shelf life. The volume of 4T pan bread was improved by the addition of 5% ovine whey powder. In the case of 48T, the volume of bread was negatively affected by the addition of ovine whey powder. Moreover, flat bread made with 4T was more extensible after the addition of ovine whey powder and showed lower starch retrogradation over time than the same type of bread made with 48T. Among the different pan bread types, consumers preferred 4T with 5% of substitution, which also showed an improved cell size distribution in the crumb.

Individual Variation in PROP Status, Fungiform Papillae Density, and Responsiveness to Taste Stimuli in a Large Population Sample

Despite considerable research investigating the role of 6-n-propylthiouracil bitterness perception and variation of fungiform papillae density in food perception, this relationship remains controversial as well as the association between the 2 phenotypes. Data from 1119 subjects (38.6% male; 18-60 years) enrolled in the Italian Taste project were analyzed. Responsiveness to the bitterness of 6-n-propylthiouracil was assessed on the general Labeled Magnitude Scale. Fungiform papillae density was determined from manual counting on digital images of the tongue. Solutions of tastes, astringent, and pungent sensations were prepared to be moderate/strong on a general Labeled Magnitude Scale. Four foods had tastants added to produce 4 variations in target sensations from weak to strong (pear juice: citric acid, sourness; chocolate pudding: sucrose, sweetness; bean purée: sodium chloride, saltiness; and tomato juice: capsaicin, pungency). Women gave ratings to 6-n-propylthiouracil and showed fungiform papillae density that was significantly higher than men. Both phenotype markers significantly decreased with age. No significant correlations were found between 6-n-propylthiouracil ratings and fungiform papillae density. Fungiform papillae density variation does not affect perceived intensity of solutions. Responsiveness to 6-n-propylthiouracil positively correlated to perceived intensity of most stimuli in solution. A significant effect of fungiform papillae density on perceived intensity of target sensation in foods was found in a few cases. Responsiveness to 6-n-propylthiouracil positively affected all taste intensities in subjects with low fungiform papillae density whereas there were no significant effects of 6-n-propylthiouracil in those with high fungiform papillae density. These data highlight a complex interplay between 6-n-propylthiouracil status and fungiform papillae density and the need of a critical reconsideration of their role in food perception and acceptability.

Osmo-dehydration of fig fruits with five sugars

Fig fruits were subjected to osmotic dehydration by means of five different sugar syrups, in order to check the aptitude of the species to this kind of processing. Osmotic dehydration was carried out at 25°C and at atmospheric pressure on whole fig fruits of the local cultivar Verde. Processing lasted 24 h and the following dehydrating syrups were used: sucrose, glucose, fructose and two commercial hydrolysed corn starch syrups, Frudex 70 and Glicosa. At fixed intervals (0, 1, 2, 3, 6, 12 and 24 h) appropriate determinations were done on fruit pulp, in order to calculate weight loss, water loss, solid gain and normalised solid content. Results obtained with no doubt indicate that whole fig fruits show a low aptitude to be osmo-dehydrated, probably for their morphology and anatomy and for processing conditions used in this trial.