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…

Infrared thermography assisted control for apples microwave drying

A microwave based system was developed for drying of apple slices while on-line controlling their temperatures. An infrared thermography assisted control system allowed to realize temperature control by detecting the instantaneous maximum temperature among the samples under test instead of a chosen slice. The effectiveness of the system at hand in realizing temperature control both in space and in time was proven for three temperatures: 55, 65 and 75 C. Temperature fluctuations became larger both with time increasing and with rising temperature levels thus causing a negative impact on dried fruit quality. In fact apples slices dried at 75 C by microwave showed L⁄ (lightness) and white index…

Molluscs shelf-life extension

La conservazione di tranci di storione con imballaggi attivi

Physical and chemical changes in minimally processed green asparagus during cold-storage

The purpose of this research is to study effects of an innovative packaging method on the shelf-life of minimally processed green asparagus. The physical-chemical parameters analyzed (weight loss, colour, texture, chlorophyll and citric acid), and monitored by untrained panellists during the cold storage period at 6 degrees C, showed that pairing of a semi-permeable film with an adsorbent material and immersion in ascorbic acid solution were able to extend the shelf-life of green asparagus. Also, on the basis of the results obtained, a study of the chlorophyll and toughness degradation kinetics of green asparagus was conducted during cold storage. These data showed the toughening of asparag…

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

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…

Effects of an innovative dipping treatment on the cold storage of minimally processed Annurca apples

The effect of trehalose as an edible coating on minimally processed Annurca apple slices was studied during cold storage. The edible coating was prepared by dipping the fruit in a solution containing trehalose at 0.8%, sucrose at 1.0% and sodium chloride at 0.1%. During storage at 6 degrees C the following parameters were monitored: weight loss, colour (hue angle (h degrees) and whitening index (WI)), firmness, malic and ascorbic acids, polyphenol content.. microstructure by scanning electron microscopy (SEM) and microbial count. The results showed that such a coating reduced the browning phenomena; in fact the WI and h degrees values were significantly lower in coated samples than untreate…

Effect of alginate-based coating charged with hydroxyapatite and quercetin on colour, firmness, sugars and volatile compounds of fresh cut papaya during cold storage

AbstractActive alginate-based coatings with quercetin glycoside and complexes of hydroxyapatite/quercetin-glycoside were used to study the shelf life of fresh cut papaya stored at 6 °C. Hydroxyapatite was used as a carrier for the release of the bioactive compound. The parameters considered affecting the quality of the fruit during storage were weight loss, color, texture, sugars and volatile compounds. Active coatings with hydroxyapatite and quercetin glycoside proved a higher capacity to slow down the degradation phenomena studied, showing less weight loss, a lower reduction in glucose and fructose, as well as better firmness, than the other samples after 14 days of cold storage. Benzyl i…

Volatile Compounds in Red Wines Processed on an Industrial Scale by Short Pre-fermentative Cold Maceration

Nero d’Avola and Shiraz grapes were subjected to pre-fermentative cold maceration at 4°C for about 24 h in industrial winemaking, in order to evaluate the effects of the pre-treatment on aroma profile. The volatile compounds were identified by gas chromatography-mass spectrometry and grouped into 14 chemical families 4 and 9 months after bottling. Principal components analysis (PCA) plots of the volatile compounds showed clear separation among wines from the Shiraz and Nero d’Avola varieties. For instance, Shiraz wines were characterized along the PC1 axe by esters of organic acids, norisoprenoids and C6 alcohols, while Nero d’Avola wines were characterized by acetates and monoterpenic oxid…

Qualitative characteristics of four Sicilian monofloral honeys from Apis mellifera ssp. sicula

Four monofloral honeys, obtained from the Sicilian black bee by foraging on thistle, sulla, chestnut and eucalyptus, were studied. Results showed that the phenolic composition of chestnut honey was the highest (316 mg gallic acid equivalent GAE/kg), while that of sulla honey was the lowest (122 mg GAE/kg). Data confirmed a correlation between the total phenol content and colour intensity in chestnut honey, which was the darkest of the four samples. Sulla honey showed the highest antioxidant activity, while eucalyptus honey had the highest mineral content (K, Ca, Mg, and Na). Thistle honey showed the most intense floral and fruity aromas, as well as an intense -yellow colour. Principal compo…

Kinetics of carotenoids degradation and furosine formation in dried apricots (Prunus armeniaca L.)

Abstract 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…

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 (…

Alginate-based coatings charged with hydroxyapatite and quercetin for fresh-cut papaya shelf life

In this study, the effect of alginate-based coatings charged with quercetin glycoside compounds and hydroxyapatite/quercetin glycoside compounds (HA/QUE) on the microbiological quality, and on bioactive compounds of fresh-cut papaya, was evaluated for 14 days at 6 degrees C. Alginate coatings with hydroxyapatite/quercetin showed a high capability to slow down the growth of all microbiological parameters investigated. At the end of cold storage, the total bacteria count in papaya samples covered with HA/QUE alginate coating was 4.8 log CFU g(-1) which is significantly lower (P < 0.05) than 8.3 log CFU g(-1) for uncoated samples. Total carotenoids' percentage decrease, at the end of storag…

Quality and volatile compounds in red wine at different degrees of dealcoholization by membrane process

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 unc…

Effect on Orange Juice of Batch Pasteurization in an Improved Pilot-Scale Microwave Oven

The effects on orange juice batch pasteurization in an improved pilot-scale microwave (MW) oven was evaluated by monitoring pectin methyl-esterase (PME) activity, color, carotenoid compounds and vitamin C content. Trials were performed on stirred orange juice heated at different temperatures (60, 70, 75, and 85 degrees C) during batch process. MW pilot plant allowed real-time temperature control of samples using proportional integrative derivative (PID) techniques based on the infrared thermography temperature read-out. The inactivation of heat sensitive fraction of PME, that verifies orange juice pasteurization, showed a z-value of 22.1 degrees C. Carotenoid content, responsible for sensor…

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 …

Antioxidant activity and sensory attributes of tomatoes dehydrated by combination of microwave and convective heating

Tomato halves were dried in a combined microwave-hot air system. Drying experiments were carried out by applying the microwave energy (0.5 W/g) at the beginning of the dehydration process (for 2 and 3.5 hours); simultaneously combining microwave (0.25 W/g) with convective hot-air drying (70°C); and by applying only convective hot air at 70°C. The combined microwave-hot air heating reduced significantly the drying time (up to 50 %), if compared with the only convective system. Simultaneous convective and microwave heating allowed besting preserving antioxidant activity of dried tomatoes, by minimizing lycopene and phenols losses, while ensuring satisfied texture characteristics and less perc…

Rapid Assessment of Gray Mold (Botrytis cinerea) Infection in Grapes with a Biosensor System

Abstract: 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 w…