Fatty acid composition, cholesterol content and lipid oxidation indices of intramuscular fat from skeletal muscles of beaver (Castor fiber L.).

The lipid characteristics of the intramuscular fat (IMF) from skeletal muscles of different beaver carcass parts (the loin, hind leg and shoulder) were characterised in detail for the first time. The shoulder muscles had higher (P < 0.05) proportion of n-3 polyunsaturated fatty acids (PUFA) than the loin muscles, which had higher percentages of saturated fatty acids (SFA), odd-chain fatty acids (OCFA) and sum of conjugated linoleic acids (ΣCLA). Moreover, the shoulder muscles were found to contain higher fat, cholesterol and total fatty acids (FA) concentrations, as well had a beneficial fatty acid profile, especially in terms of the absolute content of PUFA and some nutritional FA indices (thrombogenic index and SFA/PUFA), as well as FA ratios (n-6/n-3 and PUFA/SFA). No differences (P > 0.05) in lipid oxidation parameters (FFA, PV and TBARS) were observed between muscles from different carcass parts. Irrespective of muscle location, the predominant class of FA in IMF of beaver was PUFA (averaging 49.39%), followed by SFA (27.81%) and MUFA cis (15.96%). Linoleic acid (LA, 18:2 n-6) was the most abundant FA in all muscles (>34% of total FA). Minor percentages of unusual FA (OCFA, trans FA and branched-chain FA), which are more typical for ruminants than monogastric animals, were also detected (3.46%, 1.92% and 1.22%, respectively).

Concentration of Minerals in Nectar Honeys from Direct Sale and Retail in Poland.

The aim of the study was to compare the content of selected minerals in different nectar honeys (acacia, buckwheat, raspberry, linden, rapeseed, and multifloral) available on the Polish market. The degree to which the demand for eight minerals (K, Na, Mg, Ca, Zn, Fe, Mn, Cu) by adults is met by a portion of 100 g of honey was estimated as well. The material consisted of 34 artisanal honeys from direct sale and 34 samples purchased from retail stores. The artisanal honeys contained significantly more K, Mg, and Mn, but significantly less Na and Fe than the honeys purchased from the retail stores. The raspberry honey contained significantly the most K and Ca (1104.7 and 68.8 mg kg-1), the multifloral honey contained the most Ca and Mg (68.5 and 48.0 mg kg-1), and the buckwheat honey contained the most Zn and Mn (3.97 and 4.96 mg kg-1). The highest content of Na was shown in buckwheat and linden honeys (79.1 and 80.0 mg kg-1). Consumption of 100 g of honey from direct sale satisfied from 2.5 to 4.5% of the recommended intakes for K and from 10.4 to 17.3% for Mn, while the same portion of honey from retail satisfied from 1.6 to 4.8% for Fe, and from 2.3 to 6.1% for Zn and Cu. The buckwheat honey met to the greatest degree the recommended dietary intakes for Mn (16.5-27.6%), followed by raspberry honey (10.0-16.7%) and multifloral honey (6.9-11.6%).

Effect of freezing and room temperatures storage for 18 months on quality of raw rapeseed honey (Brassica napus).

The physicochemical properties, colour characteristics and dynamic viscosity of fresh rapeseed honey (control, CON) and those stored for 18 months at room temperature (RT) or in freezer (FRO) were compared. The significant decrease of pH after storage was found. Honey stored at RT showed an increase of 5-hydroxymethylfurfural (HMF) (+543.0 %) and decrease of diastase activity (-24.4 %), while in FRO samples the decreasing course (-50.5 and -7.3 %, p > 0.05) were found in comparison with CON samples (3.07 and 28.37 mg kg-1). The negative correlation between HMF content and diastase activity was found. The temperature of storage significantly influenced colour parameters, however, RT differentiated colour of honey to a greater extent (ΔE = 20.37) than FRO (ΔE = 8.07). The lightness (L*), hue (h°), whiteness index (WI) and colour intensity (ABS450) of CON honey samples were similar to honey from FRO. The dynamic viscosity was significantly higher in honey stored in FRO in comparison to CON honey and honey stored at RT. However, in comparison with CON honey, higher (almost twice) viscosity for honey stored at RT was observed.

Characterisation of viscosity, colour, 5-hydroxymethylfurfural content and diastase activity in raw rape honey (Brassica napus) at different temperatures.

The effect of heating at various temperatures (30, 40, 50, 60, 70 and 80 °C) on dynamic viscosity, colour, 5-hydroxymethylfurfural (5-HMF) concentration and diastase activity of raw rape honey were assessed. In fresh honey, moisture, ash, free acidity, pH and electrical conductivity averaged 185.3 g kg(-1), 1.2 g kg(-1), 18.71 mEq kg(-1), 4.2 and 0.25 mS cm(-1), respectively. Heating significantly (p ≤ 0.05) increased lightness (L*), yellowness (b*), chroma (C*), hue (h°) values, but decreased redness (a*). The viscosity at 20 °C (33.6 Pa s) differed significantly (p ≤ 0.01) with those at 30, 40 and 50 °C (8.2, 2.5, and 1.6 Pa s, respectively). Diastase activity decreased concomitant with heating at higher temperatures. Honey heated at 80 °C for 15 min showed the maximum increase of 5-HMF content, with an average of 1.9 mg kg(-1) (62 %), compared to unheated samples. Heating for 15 min between 50 °C and 80 °C did not significantly degrade the quality of the honey, but, slightly enhanced formation of 5-HMF and reduced the diastase activity.