ALPHA-LINOLENIC ACID AND LINOLEIC ACID IN SERUM AND TISSUES AFTER FLAXSEED (Linum usitatissimum) OIL IN VIVO ADMINISTRATION

Essential fatty acids can be helpful in the prevention of several pathologies. The bioavailability of acute supplementation of different doses of flaxseed oil was studied by analyzing the level of alpha-linolenic acid (ALA) and linoleic acid (LA) in serum and tissues (adipose, liver) of rats tested at 2, 4, 8 and 16 h after the administration. The amount of flaxseed oil administered at increasing doses corresponded to 1, 2.5 and 5 g ALA/kg of body weight. The corresponding fatty acid methyl esters obtained via direct methylation were quantified using gas chromatography/mass spectrometry. Serum ALA level increased after 1 or 2.5 g/kg. ALA was increased in both adipose and liver tissue 4 h after the administration of 1 g/kg of flaxseed oil. There was no further increase by using a higher oil dosage. LA did not change in serum at the doses used.

PRACTICAL APPLICATIONS

The bioavailability of acute supplementation of increasing doses of flaxseed oil was examined by analyzing the level of alpha-linolenic acid (ALA) (ω3) and linoleic acid (ω6) in serum and tissues (adipose, liver).These data suggest that there is a limiting step in the absorption of these fatty acids and that there is no advantage to take more than 1 g/kg of ALA supplementation. The daily use of flaxseed oil could be a good alternative in some cases to fish oil in the prevention of several pathologies.     

Elevation of Liquidus Temperature in a Gel-Derived Na2O-SiO2 Glass

The liquidus temperatures of a 19 wt% soda-silica glass prepared by gel and conventional techniques were determined. X-ray diffraction measurements of the glasses which were heat-treated at several temperatures were used to experimentally determine the liquidus temperatures. It was found that the gel-derived glass has an elevated liquidus. This result is discussed in relation to the previous discovery that the immiscibility temperature of this gel-derived glass is elevated.     

ANTIOXIDANT CAPACITY,SCAVENGING RADICAL ACTIVITY AND SELECTED CHEMICAL COMPOSITION OF NATIVE APPLE CULTIVARS FROM CENTRAL EUROPE

ABSTRACT

The main aim of this study was to focus on 10 typical native apple cultivars from Central Europe and to determine the basic characteristics such as dry matter, soluble solid content, titrable acidity, the content of pectins, phenolics, ascorbic acid, antioxidant capacity and the scavenging effect of 10% apple fruit extracts on hydroxyl radical, nitric oxide and superoxide radical in them. In our experiments, it was found out that the highest content of organic acids was shown by the “Jeptiska” cultivar (5.40 g/kg of FM). As far as the content of pectins was concerned, the highest levels were found out in the “Strymka” cultivar (32.60 g/kg FM). In case of total phenolic content, antioxidant capacity, ascorbic acid content and scavenging activity of reactive oxygen species (hydroxyl radical, nitric oxide and superoxide anion), high efficiency was determined in the local cultivars, namely, in “Matcino,”“Panenske ceske” and “Strymka.”

PRACTICAL APPLICATIONS

The results shown have wide use in the alimentary industry and human nutrition as apples belong to the most widespread core fruit. There exist many apple cultivars that have not been described in detail in literature and this study provides an insight into 10 not very common cultivars in the world; and although in Central Europe these cultivars are cultivated successfully, so far they have not been utilized commercially. However, their genetic uniqueness represents an irreplaceable ecological wealth and for that reason these local cultivars could become a new and outstanding source of nutrients and food. Today, they can also be used as a potential material for further breeding and selection.     

Oil Uptake in Deep Fat Frying as Affected by Porosity

The porosity of a restructured potato product ranged from 0.089 to 0.168 after fluctuating subfreezing storage temperatures. A linear relation was found between oil uptake during frying and porosity prior to frying. Bulk and particle density, and porosity were monitored for up to 5 min during deep-fat frying. Particle density increased gradually, bulk density decreased and porosity increased noticeably. After an initial short period, oil uptake correlated linearly with porosity of the fried product. A new term, “net porosity” which excluded the void volume occupied by oil was developed for describing the oil uptake mechanism.     

A COMPARISON BETWEEN TWO METHODS FOR THE RECOVERY OF LISTERIA MONOCYTOGENES IN MILK POWDER REFERENCE SAMPLES

Two methods (A and B) for the recovery of Listeria monocytogenes were compared using reference samples based on spray drying of milk containing this pathogen and competitive microflora. For method A, the sample was inoculated in a buffered liquid medium (same as IDF Pre-enrichment Broth) and then passed to IDF Enrichment Broth plus phosphate buffer. For method B, the sample was inoculated in FDA Enrichment Broth (LEB) and then passed to LEB (subenrichment). The solid selective medium used in both cases was Listeria Selective Agar (Oxford formulation). The sensitivity and specificity of method B was 95.2% and 100% vs. 76.1% and 88.8% for method A, respectively.