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The paper investigated the effect of a physical surface abrasion of goji berries on drying kinetics and the evolution of phenolic compounds at 323, 333, and 343K. A diffusion model was developed to describe the drying process. The effective diffusion coefficient estimated by the model ranged from 7.5 × 10–9 to 4.2 × 10–8 m2/s for cylinder and 2.0 × 10–9 to 1.15 × 10–8 m2/s for sphere for untreated samples (UTR). Higher values were found for treated samples (TR) (from 2.50 × 10–8 to 1.20 × 10–7 m2/s for cylinder and 8.0 × 10–9 to 2.70 × 10–8 m2/s for sphere). For the UTR samples, the values of activation energy were found to be 79.5 and 80.8kJ/mol, respectively, in the cylinder and sphere models, which decreased to 72.0 and 55.8kJ/mol for the TR samples. Catechins and cinnamic acids were the main phenols in goji berry. TR samples showed high antioxidant activity owing to the shorter exposure time to high temperatures and to oxygen. Practical applications: The fruit of Lycium barbarum is known for its nutritional properties and health benefits. Dried goji berries are consumed as a snack or they are added as ingredients in other foodstuffs. The drying of goji is difficult because the berry contains an outer layer of peeled wax, which does not allow moisture escape from the inside to the outside.The physical surface abrasion pretreatment here proposed before convective air drying helps in reducing the time and energy required for goji drying. The dried berries so obtained exhibit better nutritional quality and good appearance respect to the untreated ones. The use of this pretreatment combined with the best hot air drying conditions identified by the developed diffusion model, could represent an effective innovation in order to obtain dried products with high physicochemical properties. Furthermore, these dried goji berries have no sulfites added as a preservative.

This study investigated the effect of different degrees of dealcoholization on volatile compounds, phenols and sensory characteristics of red wine (cv. Montepulciano d’Abruzzo). The wine with an initial alcohol content of 13.2% v/v was partially dealcoholized by membrane process with a decrease of alcohol degree as follows: − 4.9; − 6.3; − 7.8, − 9.2 and − 10.5% v/v. Osmotic distillation has proved effective in preserving a satisfactory odorous profile, as samples with an alcohol residue of 8.3% v/v (− 4.9%) and 6.9% v/v (− 6.3%) showed good esters retention: more than 84% and 82%, respectively. Similarly, colour and taste, evaluated by flavonoids and phenolic compounds, remained almost unchanged in all dealcoholized samples. Lastly, the trials highlighted that dealcoholized wine up to an alcohol content of about 5.4% v/v (− 7.8%) was still perceived as acceptable by the tasters.

In order to evaluate the influence of an abrasive pre-treatment and drying at 50 °C, 60 °C, 70 °C of goji fruits (Lycium barbarum L.), changes in colour and carotenoids were studied. An extraction method was modified and adapted to assay the main carotenoid esters and saponified carotenoids of goji berries, before and after treatments. Goji berries were confirmed as a high source of zeaxanthin, with zeaxanthin-dipalmitate at about 2 g/kg dry weight. The reliability of the analytical method was confirmed by the high quantitative recoveries, about 100%, a higher repeatability than reference methods and a good reproducibility (lower than 5%). After drying, significant but small carotenoid losses (15–20%) were observed in both pre-treated and treated samples. The xanthophyll esters confirmed to be more stable than free carotenoids. The drying process significantly modified colour, in both pre-treated and untreated samples, however, pre-treatment reduced drying time and thus better preserved the colour of the goji berries for a drying temperature up to 60 °C. © 2018 Elsevier Ltd

The kinetics of carotenoid and color degradation, as well as furosine formation, were investigated in apricot fruits during convective heating at 50, 60 and 70 °C. Degradation of carotenoids and color, expressed as total color difference (TCD), followed a first and zero order kinetic, respectively. The activation energy (Ea) for carotenoids degradation ranged from 73.7 kJ/mol for 13- cis -β-carotene to 120.7 kJ/mol for lutein, being about 91 kJ/mol for all- trans -β-carotene. Violaxanthin and anteraxanthin were the most susceptible to thermal treatment. The furosine evolution was fitted at zero order kinetic model. The Ea for furosine formation was found to be 83.3 kJ/mol and the Q 10 (temperature coefficient) varied from 1.59 to 4.14 at the temperature ranges 50–60 °C and 60–70 °C, respectively.

Botrytis cinerea is the causative agent of gray mold disease, which causes considerable economic losses to winemakers. The extent of gray mold infection of winegrapes is commonly visually estimated, a method that is prone to assessor bias. Here, we used rapid and simple enzyme-based screening consisting of carbon-electrode, screen-printed amperometric biosensors to estimate gluconic acid and glycerol concentration in winegrapes infected with different degrees of B. cinerea. The lower limits of quantification of the screen-printed amperometric biosensors were 3 mg/L for gluconic acid (corresponding to an infection rate of less than 1%) and 35 mg/L for glycerol; the response times with a flow rate of 0.5 mL/min were in a range of 0.5 to 2 min in the linear ranges of the two assays. This study demonstrates the efficacy of amperometric biosensors for rapid analysis of gluconic acid and glycerol in grapes. The measurements confirmed that concentrations of both compounds are highly correlated with the rate of B. cinerea infection (R2 = 0.98). Thus, the biosensor developed to measure gluconic acid in grapes (or must) was more precise and gave a faster response than methods that currently exist for determining the rate of B. cinerea infection of grape berries.

An alternative physical method for enhancing the drying rate of plums is proposed. It consists of the superficial abrasion of the plums' peel using an inert abrasive material to remove the cuticular waxy layer, the limiting factor for moisture loss. The physical pre-treatment was compared with a chemical treatment in which the plums were dipped into a solution of ethyl oleate. The drying kinetics of the above samples, including the untreated one, were reconstructed by using a mathematical model. The drying process, carried out at 60 C to reduce the prunes' quality loss, showed the great capability of both pre-treatments to enhance water diffusivity in the plum peel with respect to the untreated samples. Moreover, it was found that the physical treatment was more effective than the chemical one. (C) 2002 Elsevier Science Ltd. All rights reserved.

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 phenols in the oils was found to be directly related, even if to a low degree, to the oleuropein content in the olives and inversely related, to the same degree, to (3,4-dihydroxyphenyl)ethanol. The latter is a derivative of oleuropein; (3,4-dihydroxyphenyl)ethanol content increases as the olives ripen, but it is very low in fresh virgin olive oils, owing to the hydrophilic nature of the phenolic alcohol, which goes mainly into the waste-water during processing. Among the varieties considered, Coratina oils showed the highest resistance to forced oxidation because of their high total phenol content.

In this paper an alternative physical method for enhancing the drying rate of seedless grapes is proposed. It consists of the superficial abrasion of the grape peel using an inert abrasive material. The effectiveness of this novel process was compared to that of the traditional ethyl oleate dipping process by analysing not only their respective drying times, but also the peel surfaces by scanning electron microscopy. Moreover, the drying kinetics of the above two treatments was reconstructed by using a mathematical model in which the grape pretreatment used was assumed to affect the water diffusivity in the grape peel, but not in the grape pulp. Even though the abrasion method was found to be as effective as the traditional method and gave rise to a darker final product, which is less attractive to consumers, it would allow grape pretreatment thus avoiding the use of chemical additives, and permit safer raisins to be produced. (C) 2000 Elsevier Science Ltd. All rights reserved.