The quality of sliced carrots affected by modified polyethylene foil and storage temperatures

The aim of this study was to examine the influence of different additive contents for oxygen absorption (5, 10 and 15%) in low-density polyethylene (PELD) plastic foils and storage temperatures (4 and 28 °C) on the quality and shelf-life of sliced carrots during storage. Quality and storage-life of packaged carrots slices were determined by observing changes of mass, total carotenoide pigments, microbial counts (mesophilic aerobic bacteria, enterobacteria, sulphite-reducing clostridia, yeast and moulds), sensory quality and texture by the use of penetrometer. The PELD foils modified with 10 and 15% of oxygen absorber (O2, CO2 and N2 permeability at 4 °C of around 700 ml m-2d-1atm-1) were the most suitable for the storage and prevention of deterioration of minimally processed carrots. Findings indicated that in these foils the best quality and shelf-life of carrot were maintained by 6 days of storage at 4 °C, without significant changes in parameters studied. The absorber for oxygen added to the foil had no influence on the permeability to CO2, O2and N2. The permeability of foils, which were used for carrot packaging increased by the increase of storage temperature to 28 °C and decreased by decreasing the temperature to 4 °C, and was not significantly affected by the additive content either. In the same time the diffusion constants of unused and used PELD foils for carrot packaging at 4 °C and 28 °C changed according to the change of film permeability during storage at those temperatures

The effect of ripening and storage on peach pectin and gel strength of related jams

Peaches were harvested in three stages of ripeness (threshold-mature - I, firm-ripe - II and ripe - III). Firm-ripe (II) peaches were stored for 9 days at 4 and 22 C. The amount of water-soluble, oxalate-soluble and alkali-soluble pectin were extracted and quantitatively determined as galacturonic acid, neutral sugars were determined as glucose. Jams were made with all peach samples as well as gels from extracted fractions. Gel strength of jams and gels was measured.  Dry matter, sugar composition (amount of sucrose and reducing sugars) and pH value were determined and very little change was found during the ripening period and storage, too.  Alkali-soluble fraction was more abounding than water-soluble fraction. The oxalate-soluble pectic fraction was found to be a minor fraction in all peach samples. The amount of total pectin and the amount of alkali-soluble pectin fraction dropped markedly after the 1st stage of ripening, after the 2 nd day of storage at 22 C and slightly after the 6th day of storage at 4 C. The level of alkali-soluble pectin in total pectin was inversely proportional to the level of water-soluble pectic fraction, and the level of oxalate-soluble pectic fraction in total pectin content was fairly constant during the ripening and storage. Gel strength of jams and gels correlated very well with changes of the amount of alkali-soluble pectic fraction.  The extracted alkali-soluble pectic fraction was capable of forming an acidic gel. Extracted oxalate-soluble pectic fraction forms a gel in the presence of calcium and solid matter more than 77%.  It seems that the amount of alkali-soluble pectic fraction in peaches is responsible in producing peach jams according to gel strength

Effect of drying conditions on indole glucosinolate level in broccoli

Broccoli is interesting as raw vegetable for domestic use and as well as dehydrated powder due to content of numerous biologically active compounds — phytochemicals. We examined the influence of blanching and drying air temperature and velocity on glucosinolate composition and content under conditions which are usually applied in industrial processing of broccoli. Broccoli blanching prior to drying caused a significant decrease in the glucosinolate content, which additionally decreased during the drying process. Drying at 50 °C and 60 °C with air velocity of 2.25 m s−1 was the most favourable in most of the cases

Sources, stability, encapsulation and application of natural pigments in foods

In recent years, the replacement of synthetic colorants with natural ones has attracted increasing consumers’ and market interest. Natural colorants include different groups of pigments, many of which possess also pronounced biological potential. This review addresses the main issues related to the use of natural pigments in foods, starting from the sources available in nature, their chemical properties, stabilization processes, and applications in real foods, as discussed in the scientific literature reported in the main databases relevant to this topic (Scopus, Web of Science, PubMed, ScienceDirect, and Google Scholar). Notably, several natural pigments are available to cover different needs in terms of hues and intensities, and whose use is permitted in foods by the main regulatory agencies. However, their use is still frequently limited by their higher price and lower stability than synthetic counterparts. This review discusses in detail the main sources for natural pigments, focusing on the recent trends towards those more economically favorable, such as microbial sources and agro-industrial residues. It also examines the most suitable stabilization systems to protect the highly reactive and unstable molecules of natural pigments from negative physical and chemical changes, as well as to minimize the interactions with food systems

Absorption, Metabolism, and Excretion of Cider Dihydrochalcones in Healthy Humans and Subjects with an Ileostomy

The phloretin-O-glycosides, phloretin-2GǦ-O-glucoside and phloretin-2GǦ-O-(2GǦGǦ-O-xylosyl)glucoside, are thought to be unique to apples and apple products. To investigate the metabolism and bioavailability of these compounds, nine healthy and five ileostomy human subjects consumed 500 mL of Thatchers Redstreak apple cider containing 46 ++mol of phloretin-O-glycosides. Over the ensuing 24 h period, plasma, urine, and ileal fluid were collected prior to analysis by high-performance liquid chromatographyGêÆmass spectrometry (HPLCGêÆMS). The sole metabolite present in quantifiable amounts in plasma was phloretin-2GǦ-O-glucuronide, which reached a peak concentration (Cmax) of 73 nmol/L and 0.6 h after ingestion (Tmax) with the healthy subjects, and statistically similar values were obtained with the ileostomy volunteers. Phloretin-2GǦ-O-glucuronide was also detected in urine along with two additional phloretin-O-glucuronides and a phloretin-O-glucuronide-O-sulfate. The quantity of phloretin metabolites excreted in urine represented 5.0 -¦ 0.9% of intake in healthy volunteers and 5.5 -¦ 0.6% in ileostomy volunteers. The similarity in the excretion levels of the two groups and the rapid plasma Tmax indicate absorption of the dihydrochalcones in the small intestine. Of the two major phloretin-O-glycosides in cider, only phloretin-2GǦ-O-(2GǦGǦ-O-xylosyl)glucoside was recovered in ileal fluid in quantities corresponding to 22% of intake. The absence of phloretin-2GǦ-O-glucoside in ileal fluid suggests that it is more readily absorbed than phloretin-2GǦ-O-(2GǦGǦ-O-xylosyl)glucoside. Phloretin-2GǦ-O-glucuronide, two other phloretin-O-glucuronides, one phloretin-O-glucuronide-O-sulfate, two phloretin-O-sulfates, and the aglycone phloretin were also detected in the ileal fluid. This implies that the wall of the small intestine contains +¦-glycosidase, sulfuryltransferase, and UDP-glucuronosyltransferase activities and that, as well as being absorbed, sizable amounts of the phloretin metabolites that are formed efflux back into the lumen of the gastrointestinal tract. The overall recovery of the dihydrochalcones and their metabolites in the ileal fluid was equivalent to 38.6% of intak

Assessment of the Bioactive Compounds, Color, and Mechanical Properties of Apricots as Affected by Drying Treatment

Consumer acceptance of dried apricots depends on them having an intense orange color, a gummy texture, and a characteristic flavor. In addition, the growing demand for healthy and nutritive foods has increased the interest in this product, as apricot fruits can be considered a good source of phytochemicals, such as polyphenols, carotenoids, and vitamins. Microwave energy may be an interesting drying method, an alternative to conventional sun or hot air drying, with which to obtain dried apricots with good sensorial, nutritive, and functional properties in a shorter time. This paper aims to evaluate the effect of sulfur pretreatment and the drying process (hot air and/or microwaves) on the color, mechanical properties, and ascorbic acid, vitamins A and E, and total carotenoid content of apricot. 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