Oxidative stability of virgin olive oils
An investigation was carried out on virgin olive oils of the Gentile (Larino), Gentile (Colletorto), Coratina, and Leccino varieties, harvested at different times, to assess their oxidation stability. The olive oils were analyzed by means of peroxide, K-232, and K 270 values at 1, 6, 12, and 18 mon of storage in green bottles, in the dark, at temperatures ranging from a mean of 6degreesC in winter to 12degreesC in summer. A subsample was also oven-tested at 75degreesC and then analyzed on a weekly basis using the same oxidative parameters. The less ripe the olives (harvested in the same area, during 1 mon), the more resistant the olive oils were to forced oxidation. The amount of total phen…
Phenolic compounds in different olive varieties
Phenolic compounds in different olive varieties were determined by HPLC analysis over 2 years. Demethyloleuropein was found in only two (Coratina and Leccino) of the eight varieties studied, so it could be used as varietal marker. Elenolic acid glucoside and hydroxytyrosol can be considered indicators of maturation for olives. In fact, as the olives ripen, their tenor increases whereas oleuropein decreases. Keywords: Phenolic compounds; olive fruit; oleuropein; demethyloleuropein; 3,4-dihydroxyphenylethanol; elenolic acid glucoside
Evolution of phenolic compounds virgin olive oil during storage
Phenolic compounds are of fundamental importance to the shelf life of virgin olive oils because of their antioxidative properties. In this paper, the evolution of simple and complex olive oil phenols during 18 mon of storage is studied by high-performance liquid chromatography (HPLC) analysis. The olive oils under examination were from various olive cultivars, harvested in two sectors in the same region at different stages of ripeness. The findings indicate that it is not the variety but rather the ripeness of the olives and the soil and climate that influence the phenol composition of virgin olive oil. In addition, a positive correlation was found between the age of the oils and the tyroso…
Physical pre-treatment of plums (Prunus domestica). Part 2. Effect on the quality characteristics of different prune cultivars
The effects of an alternative physical pre-treatment for enhancing the drying rate of different plums (Stanley, Angeleno(R), and Empress), are evaluated by means of the principal chemical parameters and by skin colour. The pre-treatment consists of the superficial abrasion of the plums' peels using an inert abrasive material to remove the cuticular waxy layer, the limiting factor for moisture loss. The drying process was carried out at 60 C to reduce the plums' quality loss, the latter being assessed by analysing the changes in skin colour, sugars by HPLC, total phenols, total anthocyanins, and reactive substances to the vanillin-HCl reagent. The proposed physical pre-treatment, without sig…
Physicochemical and sensory fruit characteristics of two sweet cherry cultivars after cool storage
Physicochemical and sensory fruit characteristics were studied to assess the effects of cool storage on quality attributes of sweet cherries of the Sciazza variety, widespread in the Campania region and Ferrovia variety, marketed in Italy and abroad. The major sugar and organic acid constituents, anthocyanin composition, colour (CIE L*, a*, b*), firmness, volatile neo-formation compounds (acetaldehyde, ethanol and methanol) and sensory attributes were determined at harvest and after 15 days of fruit storage at 1 degreesC and 95% RH. The ANOVA and PCA plots showed that both cherry varieties and storage conditions affected sensory/chemical quality but the variation caused by cool storage seem…