Squid (Sepia officinalis) stored in active packaging: chemical and microbiological changes

The effect of modified atmosphere packaging (MAP) with and without a moisture adsorbent, on the quality of squid (Sepia officinalis) during chilled storage, was evaluated. Chemical and microbiological tests were carried out to measure the amount of spoilage and the resulting loss of fish freshness during 12 days of storage at 3°C. After 11 days, trimethylamine nitrogen (TMA-N) increased from 0.4 mg/100 g in fresh samples to 24 mg/100 g in MAP with adsorbent and 35 mg/100 g in the other samples. Total volatile basic nitrogen (TVB-N) increased from 18 mg/100 g in fresh samples to 112 mg/100 g in MAP with adsorbent and 158 mg/100 g in control samples. Counts of aerobic psychrotrophic microorga…

Molluscs shelf-life extension

Physical pre-treatment of plums (Prunus domestica). Part 1. Modelling the kinetics of drying

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 untre…

Bread making with Saccharomyces cerevisiae CEN.PK113-5D expressing lipase A from Bacillus subtilis: Leavening characterisation and aroma enhancement

Summary Lipase A from Bacillus subtilis was expressed in the yeast Saccharomyces cerevisiae CEN.PK113-5D strain as a cell wall-immobilised enzyme. The recombinant yeast was used in bread making to test the effect of lipase A on the bread properties such as rheological and aromatic properties. The results were compared to the not transformed strain and the commercial baker's yeast. The recombinant strain resulted a good leavening agent comparable to the commercial baker's yeasts provided 1% sucrose was added to the dough. Whereas, during the leavening, the trend of the rheological properties (cohesivness, gumminess and rigidity) differed from the commercial and the nontransformed (NT) strain…

La conservazione di tranci di storione con imballaggi attivi

Conservazione di lattuga Ninjia (lactuca sativa L.) in atmosfera modificata

Drying kinetics and physico-chemical quality of mango slices

Mango (Mangifera indica L.) is an important tropical fruit consumed worldwide and grown in Italy only in Sicily, where the areas of the Tyrrhenian coast have proved to be suitable to produce valuable fruits. Mango fruit has a pleasant aroma and taste, which are important qualities for consumer’s sensorial acceptance. However, they are highly perishable, prone to progressive undesired changes if stored untreated, resulting in around 25% postharvest losses, which is further increased during storage and transportation. An alternative for reducing the above-mentioned undesired changes is the dehydration of the cut fruit, which reduce the fruit water activity, thereby avoiding the deteriorative …

The effect of abrasive pretreatment on the drying kinetics and phenolic compounds in goji berries ( Lycium barbarum L.)

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 343 K. 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 80.8 kJ/mol, respectively, in the cylinder and sphere …

Tomato peel drying and carotenoids stability of the extracts

Summary Tomato peels were firstly dried by different methods (hot air, freeze-drying, and fluidized bed drying) to evaluate the recovery of lycopene, β-carotene and DPPH radical scavenging activity. Comparison of the results showed that hot air drying at 50 °C was a suitable method and alternative to freeze-drying to preserve carotenoids compounds and antioxidant activity in tomato peels. Then, ethanol/ethyl acetate (1:1) extracts from tomato peel, previously dried at 50 °C by hot air, were submitted to heat (100 °C) and light treatment (1000 lumen) to evaluate their stability as natural food dyes. Heating of the extracts caused a progressive reduction of total carotenoids, up to about 30% …

Microwave drying of aubergine (Solanum Melongena) slices: kinetic and quality changes.

Effects of drying temperatures on physico-chemical properties of dried and rehydrated chestnuts (Castanea sativa)

This work evaluated the effects of two drying temperatures (40 and 60 degreesC) on some physical and chemical properties of chestnuts, both dried and after their rehydration using steam at 100 degreesC. The morphological characteristics of fresh starch granules were characterized by a round or oval shape, with diameter length ranging from 3.0. to 15.0 mum. After drying and rehydration, the granules appeared more shapeless and the surfaces were quite rough. The changes also caused more of the open pore volume fraction in samples dried at 60 degreesC, than in those dried at 40 degreesC and, much more, than the fresh samples. Also, calorimetric behaviour, starch and simple sugar changes after …

The effects of pre-fermentation cold maceration on the composition of Aglianico wine

The effect of pretreatments on the drying of different seedless grapes

Effect of abrasive pretreatment on hot dried goji berry

Goji (Lycium barbarum L.) is a Solanaceous deciduous shrub that grows in China, Tibet and other parts of Asia. Nowadays, goji berries are known as being very rich in nutrients with high antioxidant capacity, fact for which they were included in the novel category of “superfruits”. Goji berries contain high amounts of antioxidants, carotenoids, vitamin A and zeaxanthin. Most of goji berries produced are dried because they are very delicate fruits. Drying process improves fruit stability, since it decreases considerably the water activity of the food, reduces microbiological and enzymatic activity and minimizes physical and chemical reactions during storage. However, drying of goji berries ca…

Effect of a novel physical pretreatment process on the drying kinetics of seedless grapes

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 …

The quality of orange juice

Mild processing technologies allow to obtain OJ available year-round, with characteristics closer to those of fresh orange, namely for its content in substances exhibiting free radical scavenging and antioxidant activities. These healthy components, mainly vitamin C, carotenoids and flavonoids, exhibit different absorption kinetics, bioavailability and antiradical mechanisms. Anyway, there is greater absorption of these nutrients when taken not as singly as supplements, but when consumed in minimally processed fruit, such as OJ, in which they naturally appear along with all the other biologically active phytonutrients that citrus fruits contain. Type of processing, packaging and storage con…

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…

Degradation of Carotenoids in Apricot (Prunus armeniaca L.) During Drying Process

"Carotenoids are natural compounds whose nutritional importance comes from the provitamin A activity of some of them and their protection against several serious human disorders. The degradation of carotenoids was investigated during apricot drying by microwave and convective hot-air at 60 and 70 A degrees C. Seven carotenoids were identified: antheraxanthin, lutein, zeaxanthin, beta-cryptoxanthin, 13-cis-beta-carotene, all-trans-beta-carotene and 9-cis-beta-carotene; among these, all-trans-beta-carotene was found to be about 50 % of total carotenoids. First-order kinetic models were found to better describe all-trans-beta-carotene reduction during drying, with a degradation rate constant (…

A mathematical model of mass transfer in spherical geometry: plum (Prunus domestica) drying

In this paper the analytical solution of a mathematical model of mass transfer in spherical geometry is presented for boundary conditions useful for simulating drying processes of fruit with near spherical stones. This model is applied to analyse the efficiency of a new pre-treatment for a prune drying processes. The new proposed physical abrasion pre-treatment increases the plum drying rate at 60 degreesC. The mathematical model here presented allows a complete comparison of the experimental results obtained with this pre-treatment and with traditional ones. In particular the greater efficiency of the new physical pre-treatment appears to be due to the enhancement of the water diffusivity …

Evolution of Carotenoid Content, Antioxidant Activity and Volatiles Compounds in Dried Mango Fruits (Mangifera Indica L.)

The aim of this research was to study the evolution of carotenoid compounds, antioxidant &beta

Effects of microwave and hot-air drying methods on colour, β-carotene and radical scavenging activity of apricots

Summary The effects of drying by microwave and convective heating at 60 and 70 °C on colour change, degradation of β-carotene and the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity of apricots were evaluated. Microwave heating reduced significantly the drying time (up to 25%), if compared with convective one, also owing to the higher temperature reached during the last phase of the process, as monitored by infrared thermography. Colour changes of apricot surface, described with lightness and hue angle, in both drying methods followed a first-order reaction (0.927 ≤ R2 ≤ 0.996). The apricots dried by microwave were less affected by the darkening phenomena. The evolution of …

Effect of a novel process an the reological properties of a typical sounth- Italy product: “Castagne del Prete”