The cyclic voltammetric method, which is based on the redox properties of ascorbic acid, was adopted to determine the concentration of vitamin C in apple juices. Recorded on voltammograms, the oxidation current of ascorbic acid was linearly dependent on the ascorbic acid concentration (a linear calibration curve was found in the range of up to 150 mg ascorbic acid/100 cm³ solution). The standard addition technique was used to determine the ascorbic acid concentration. To verify results, the titrimetric method was used. Differences between concentrations of vitamin C determined using the cyclic voltammetric and titrimetric methods are lower than 1 mg (in comparison to concentrations of ascorbic acid about 50 mg/100 cm³ of juice). The method – easy for automation – can be used directly without special preparation of studied apple juices samples before measurement of the vitamin C concentration.

The method of fractionation proposed by Czuchajowska and Pomeranz [1993] was applied in the present studies to obtain the following fractions from triticale flour: gluten, water soluble substances, tailing starch, insoluble fibre and prime starch. Contents of gluten and pure starch obtained by fractionation from triticale starch were lower than those acquired from wheat flour ‘Emika’, while higher amounts of starch tailings and insoluble fibre were produced. In case of flour from wheat and triticale cultivars ‘Presto’ and ‘Vero’, fractinating resulted in the reduction of wet gluten in comparison to standard Glutomatic method.

The objective of the study was to determine quality changes of fresh and frozen (after 6 and 12 months) ‘Elsanta’cv strawberry homogenates. There were 3 variants of purée prepared: without sugar, with 5% and 10% sugar supplement. Dry weight, vitamin C, total polyphenol and total acidity were determined. Further both in fresh and frozen homogenates (after 2 days, 6 and 12 months) total count of bacteria, yeasts and moulds as well as coliform and enterococci titre were estimated. During freeze-storage of pureé the least quantitative alternations were found for dry weight and total acidity whereas the highest for vitamin C and total polyphenol content. Protective effect of sugar towards microorganisms was observed in the process of freezing. It was reflected in higher bacteria, yeast and mold counts in homogenates with 5 and 10% of sugar supplement compared to non-sugar variant. Freshly frozen homogenates showed excessive – compared to the requirements – mold and yeast counts (> 5×10² cfu∙g^-1) whereas after 6 months of storage in all the homogenates no yeasts were found, the molds were sparse and higher bacteria count (10³ cfu∙g^-1) was noticed only in 10% of sugar supplement variant. After 12 months microbiological status of all the frozen purée was similar.

Apples of ‘Szampion’ variety produced in the homestead orchards showed the highest concentration of nutrients in dry mass with, however, slight differences in mineral component contents. The highest level of fructose (24.304 g/100 g d.m.), glucose (5.207 g/100 g d.m.) and sucrose (19.015 g/100 g d.m.) was recorded in the apples harvested in Wola Sernicka, Łęczna and Puławy, respectively. The apples produced in the commercial orchard in Lublin proved the highest content of vitamin C available.

The research concerned the influence of the pH of the culture medium on the ability of binding magnesium ions, by the cells of Candia utilis ATCC 9950. In the same time, the influence of the active acidity of the culture medium enriched with magnesium on the cell biomass yield. For this purpose, pH of the YPD culture medium has been set on the 5.0, 6.0 and 7.0 and enriched in a constant dose of magnesium, namely 1.25 g/dm³ in the beginning of the 48 hours culture in dynamic condition. The biggest amounts of magnesium binding with the cells (4.26 mg/g d.w.) were present in the cells on the culture medium which pH factor was 7.0 after 48 hours. The biggest biomass yield in the experimental conditions (15.51 g d.w./dm³) was received after 24-hours culture, also on a neutral pH medium. It is possible that the active acidity was the factor of the environment which determined the ability of binding magnesium from the medium by regulating its accessibility for the outer structures of the yeast cells.

The aim of the paper was to determine the influence of the kind of acid, acidity of beverages and additive of carbon dioxide on the stability of natural β-carotene which the beverages were coloured. The beverages were made of flavour emulsions, while β-carotene was extracted from carrot by means of the rapeseed oil and/or essential oil. The stability of beverages colour was determined on the basis of β-carotene concentration disintegration during 7 days storage including the half-life decomposition time and on the basis of 12 weeks storage test. The stability of beverages colour appeared to depend on the choice of the kind of pigment preparation, acid and on the beverage pH. With decreasing the pH of beverages the stability of β-carotene increased. The stability was higher in beverages with the pH adjusted to 3.5 by means of ascorbic acid than in those with the same pH but containing citric acid. The beverages charged with carbon dioxide were characterised by a more stable colour than those not charged.

The aim of this study was to work out a recipe for fruit ice with addition of soy protein isolates. The influence of sorts and dose of hydrocolloids on the physicochemical and sensoric properties of fruit soy ice was studied. The soy and whey proteins were compared as ice stabilizer. The investigations were performed to work out recipes for soy ice containing similar contents of protein as that of based on milk or containing higher contents of soy protein up to 6.25 g in a portion of ice. The quality of products was determined on the basis of the sensory evaluation, the apparent viscosity and density of ice mixture and on the basis of overrun and melting time of the ice.

The paper had the objective of determining the physicochemical parameters of colt meat during a five-day long cold storage, tantamount to its turnover period to, or time of its reaching, the western-European countries. Samples of the longest dorsal muscle from 29 colts 1.5-2 years old, from commercial breeding were investigated. Colt meat is characterized by high content of water and protein and low content of fat. That meat requires a longer period for ‘maturing’ and, with its value pH, indicates a potential for storage in cold condition for at least five days. Moreover, a five day maturing of colt meat in cold storage raises its water holding capacity, usability for processing and improves meat tenderness, as well as causes a dramatic darkening of meat color.

The objective of this paper was to determine the effect of cold-storage time (in frozen condition) on selected physical and chemical characteristics of horsemeat and fat. Samples of the longest dorsal muscle and nape fat from horse carcasses were tested. Two time periods of 1 and 3 months were applied as a comparative criterion for meat and fat. The research was performed on 26 carcasses of adult horses (8-10 years old). It has been shown that the frozen storage process causes darkening of meat color as well as reduces the meat capacity to bind and retain water. Moreover, the frozen storage improves the meat tenderness. With the time of cold storage the peroxide value and acid number were observed to rise as the evidence of oxidizing and hydrolytic processes taken place in horse fat.

The study investigated the effect of fat substitution with a potato fiber preparation Potex on changes in the microstructure of finely comminuted meat batters and processed meat products produced from such batters. Fat was replaced with a potato fiber preparation in the amount of 1%, 2% and 3%. Microstructure of batters and processed meat products was assessed using a computer image analysis system. In batters apparent viscosity, drip loss and free water content were determined. Produced meat products were subjected to sensory examination of overall desirability of model products. The best quality products were obtained from batter produced with no fat substitution with a potato fiber preparation.

Products prepared from animal blood intended for human consumption and collected in accordance with GHP rules are considered as of high nutritional value for their use for food purposes. The properties of a globin protein prepared from red cell fraction by an enzymatic method were studied. The efficiency of process as well as functional and nutritional characteristics of hydrolysates were evaluated. Liquid preparation obtained commercially from a culture of Bacillus subtilis contained a complex of proteolytic and some amylolitic enzymes was used in the experiment. Both, time of hydrolysis (6-48 h) and enzyme concentration significantly affected the degree of decolouration of red cell fraction and all properties of preparations obtained. The preparations demonstrated various molecular weight composition. The extinction of some hydrolysates at 540 nm was lower than 0.05. When compared with spray dried blood plasma or sodium caseinate, the globin preparation obtained under chosen conditions (18 h of hydrolysis, 10 ml of enzyme solution per 100 g of red cells) and freeze dried showed good solubility. Having very good emulsifying and foaming properties, the examined preparations indicate the potential as a valuable agent for incorporation into food formulations.

The objective of this work was to study antioxidative properties of the preparations obtained from the seed coats of brown, red and white beans. To make the preparations, polyphenols were extracted using a 0.5% HCl solution in methanol, condensed under the vacuum conditions and lyophilized. In order to provide a chemical profile of the preparations obtained, the content of general polyphenols, condensed tannins and anthocyanins were determined. The antioxidative properties were determined in the presence of DPPH^● radicals, peroxyl radicals and their secondary decomposition products. Polyphenol preparation protecting activity on β-carotene was determined too. All the preparation exhibited antioxidant activity against peroxyl radicals (83-87%), secondary decomposition products (78-87%) and DPPH^● radicals (50-67%). All the preparations protected β-carotene from peroxyl radicals degradation. The preparations extracted from color beans developed the strongest antioxidative activity. This fact could be attributed to the higher contents of polyphenols in these preparations.

Antioxidant and antiradical activities of cinnamic and benzoic acid derivatives, using different methods, were investigated. The total antioxidant effect was evaluated using method with linoleic acid-water emulsion. The ability to scavenge free radicals was checked using 2,2^’-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS•) or 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•). The reducing power of the studied compounds solutions was also evaluated. It was stated, that the applied measuring method strongly influenced the obtained result, because in the system with ABTS• free radicals, the highest antioxidant activities possessed vanillic, sinapic and protocatechuic acid, whereas the most effective DPPH• radical scavengers were methyl ferulate, methyl syringate, syringaldehyde and vanillic acid. In another method, linoleic acid peroxidation was effectively inhibited by the caffeic, sinapic and syringic acid. The highest reducing powers possessed protocatechuic acid, caffeic, sinapic and ferulic acid, higher than BHT and comparable to Trolox. Methylated derivatives of coumaric acid, caffeic acid, vanillic acid and syringic acid turned out to be weaker antioxidants and reducing agents than the free forms, except methyl ferulate, which possessed only slightly lower antioxidant activity than free ferulic acid, and in some measuring systems was a more effective antioxidant than ferulic acid.