Design of Physicochemical Properties of Eggs as a Result of Modification of the Fat Fraction of Laying Feed.

The aim of this study was to investigate and confirm the properties of eggs produced by laying hens fed a diet consisting of pomegranate seed oil as a source of CLnA and flaxseed oil as a source of α-linolenic acid. The study involved determining the chemical composition of the eggs, including their fatty acid profile. The results showed that modifying the laying hens' feed composition resulted in eggs with high nutritional value, with a favorable change in their fatty acid profile. In most cases, the addition of linseed oil or pomegranate seed oil did not affect the physical and chemical properties of the eggs. However, the diet of laying hens had a positive effect on the fatty acid profile of the egg yolk. The presence of conjugated linolenic acid trienes in eggs produced by laying hens fed a modified diet makes them a potential source of these compounds for human consumption.

Red Arils of Taxus baccata L.-A New Source of Valuable Fatty Acids and Nutrients.

The aim of this study, focused on the nutritional value of wild berries, was to determine the contents of macronutrients, profiles of fatty (FAs) and amino acids (AAs), and the contents of selected elements in red arils (RA) of Taxus baccata L., grown in diverse locations in Poland. Protein (1.79-3.80 g/100 g) and carbohydrate (18.43-19.30 g/100 g) contents of RAs were higher than in many cultivated berries. RAs proved to be a source of lipids (1.39-3.55 g/100 g). Ten out of 18 AAs detected in RAs, mostly branched-chain AAs, were essential AAs (EAAs). The EAAs/total AAs ratio approximating were found in animal foods. Lipids of RA contained seven PUFAs, including those from n-3 family (19.20-28.20 g/100 g FA). Polymethylene-interrupted FAs (PMI-FAs), pinolenic 18:3Δ5,9,12; sciadonic 20:3Δ5,11,14, and juniperonic 20:4Δ5,11,14,17, known as unique for seeds of gymnosperms, were found in RAs. RAs may represent a novel dietary source of valuable n-3 PUFAs and the unique PMI-FAs. The established composition of RAs suggests it to become a new source of functional foods, dietary supplements, and valuable ingredients. Because of the tendency to accumulate toxic metals, RAs may be regarded as a valuable indicator of environmental contamination. Thus, the levels of toxic trace elements (Al, Ni, Cd) have to be determined before collecting fruits from natural habitats.

Short- and long-term retrogradation of potato starches with varying amylose content.

BACKGROUND: Gels of potato starches with varying amylose content were prepared and the degree of pasting and the course of retrogradation were studied. The average molar masses of granular and pasted starches were estimated. Determination of the degree of pasting involved use of optical microscopy and the study of pasting characteristics. The studies of susceptibility to retrogradation considered mechanical spectra, hardness, syneresis, resistant starch content, and X-ray measurements. RESULTS: Heating of the starch suspensions at 95 °C resulted in almost complete deterioration of granules. Changes in storage modulus (G') exceeded these of loss modulus (G"). Values of G' and G", hardness and syneresis increased with the period of the sample storage and, simultaneously, the relevant tangent of the phase shift angle (tg (G"/G')) decreased. A tendency was observed for the resistant starch (RS) content to increase on prolonged storage of gels. The patterns of diffractograms for the pasted and lyophilized samples only differed slightly. CONCLUSION: The pastes of all the studied potato starches were characterized by a similar degree of pasting. The most essential changes in the physicochemical properties of the gels were observed between the 30th and 90th days of storage. The susceptibility of potato starch gels to retrogradation, especially within the first 2 h, was controlled, mainly by the amylose content. © 2018 Society of Chemical Industry.

Thixotropic properties of waxy potato starch depending on the degree of the granules pasting.

This paper presents the rheological instability (thixotropy/antithixotropy) of waxy potato starch (WPS) pastes depending on their concentration (1-5% w/w) and pasting temperature (80, 95 and autoclaved: 121°C, at 0.1MPa). The hysteresis loop, apparent viscosity at constant shear rate as well as the in-shear structural recovery tests with and without pre-shearing were applied. The pastes were also characterized by the granularity profile, molecular weight, polydispersity and optical transmittance. Differences in rheological properties of the pastes prepared at 80 and 95°C as well as autoclaved resulted from degree of granules pasting. At 121 °C dissolution of the granules occurred, while at the lower temperatures only the partial pasting of the granules took place. Pasting temperature of WPS significantly influenced rheological parameters of the resulted pastes which had thixotropic, antithixotropic or mixed thixotropic/antithixotropic behavior. Autoclaved pastes, regardless their concentration were antithixotropic as demonstrated by the areas of hysteresis loops derived from the flow curves signalized by the degree of structure recovery (DSR) which exceeded unity. The apparent viscosity of WPS pasted at 121°C strongly decreased as compared to the samples pasted at lower temperatures. Samples pasted at 80 and 95°C showed both thixotropic and antithixotropic behavior, with a predominance of the latter. The starch concentration played an important role in the formation of the rheological properties of the resulted pastes. Its influence was strongly connected with the degree of the granules pasting, therefore with the temperature of pastes preparation. For the pastes prepared at 80 and 95°C the values of thixotropy and apparent viscosity increased, while the values of DSR decreased with an increase of concentration. In the autoclaved pastes the antithixotropy, DSR and apparent viscosity increased with increasing starch concentration. It was also found that apart from the concentration and temperature also the shear rate influence the thixotropic behavior.

Thixotropic properties of normal potato starch depending on the degree of the granules pasting.

The aim of this paper was the study of the rheological instability (thixotropy and/or antithixotropy) of normal potato starch (NPS) pastes depending on their concentration (2-5%) and degree of pasting. Flow curves with hysteresis loops, apparent viscosity at constant shear rate and in-shear structural recovery tests were carried out. Granule size profiles, the pasting characteristic of corresponding starch suspensions and the transmittance of the pastes, the molecular weights and polydispersity of granular starch and its pastes prepared at 80, 95 and 121°C were also studied. The degree of pasting was dependent on the temperature and the concentration and influenced strongly the rheological behavior of the pastes. All pastes belonged to the non-Newtonian liquids thinned by shear and were rheologically unstable to the various extent. Thixotropic properties were connected to the size and the number of the starch granules in the pastes as well as depended on the measuring method used. In the 2 and 3% samples pasted at 80°C the swelling of the granules prevailed their destruction (thixotropy was observed). In the other samples the destruction predominated the swelling (antithixotropy observed).

Applicability of physico-chemical parameters of honey for identification of the botanical origin.

BACKGROUND: Efforts are being made to apply physicochemical parameters analysis in the identification of varietal honeys. With many variables describing a given population, it is feasible to differentiate between basing on principal component analysis (PCA). The aim of this study was to investigate selected physicochemical quality characteristics of nectar honey, with particular emphasis paid to carbohydrate composition, and to determine its applicability in identifying the variety of floral honey. MATERIAL AND METHODS: The experimental materials were samples of commercial honey available at retail in Krakow in 2005-2007 period. The following analyses were performed: water content by the refractometric method, sugars content according to Luff-Schoorl, content of sugars using HPLC, electrical conductivity, specific rotation, and acidity of honey. RESULTS: Application of HPLC allowed the precise qualitative identification of sugars, which was impossible to be determined by Luff-Schoorl method. The obtained results were analysed using principal component analysis (PCA). CONCLUSIONS: Based on the obtained results and performing the statistical analysis, it was found that the relationship between specific rotation and the total acidity can be used to distinguish buckwheat honeys from other analysed varieties. Moreover, it was demonstrated that the relationship between the specific rotation and maltose content can be used to distinguish between acacia honeys vs. buckwheat and lime honeys.