Nutrification and fat reduction of deep-fried protein isolates.

Deep-fried (DF) foods are considered nutritionally-inferior due to increased fat content, although they are popular with consumers due to desirable sensory characteristics. This study attempted to reduce fat of DF surimi, DF fish-protein-isolate (FPI), and DF chicken-protein-isolate (CPI) by pre-baking or pre-roasting. Surimi, FPI, and CPI were also nutrified with ω-3-rich oil, fiber, and KCl-based salt substitute.

Application of a crude digestive proteases preparation to improve the ripening of marinated fillets from low-technological value Baltic herring (Clupea harengus membras L.).

Background: As a result of climate change (reduced the oxygen content and food available in the waters) and overfishing, ever larger batches of the herring catch are classified as low-value fish and used for feedstuff or canned food production. Fast and complete ripening of marinated fillets, especially from low-value Baltic herring, poses a problem because of the low muscle protease activity and changes in muscle tissue proteins.

Results: For the first time, a crude digestive proteases preparation (CDPP) was obtained from herring viscera using a two-stage method consisting of ethanol extraction and then salt precipitation.

Use of Rapid Capillary Zone Electrophoresis to Determine Amino Acids Indicators of Herring Ripening during Salting.

Currently, herring fillets are salted with acetic acid to activate muscle proteases. This causes a change in the composition of free amino acids, compared to salting of whole fish with viscera proteases. Therefore, old indicators of the ripening dynamics of salted fish based on amino acids are not current.

Development of Functional Acid Curd Cheese (Tvarog) with Antioxidant Activity Containing Astaxanthin from Shrimp Shells Preliminary Experiment.

The food industry is looking for natural additives to improve acid curd cheese (tvarog), while shrimp by-products are being wasted. The concentrated astaxanthin lipid preparation (ALP) was recovered from shrimp shells and added (0%, 0.25%, 0.

Effect of Protein Denaturation Temperature on Rheological Properties of Baltic Herring Muscle Tissue.

The technological properties of raw fish are influenced by the changes in protein structure under heating, which determines the texture and quality of the product. The aim of the study was to examine the protein denaturation temperature and the rheological properties of Baltic herring muscle tissue. The thermal properties were determined by the differential scanning calorimetry (DSC) method and the rheological properties were determined using dynamic oscillatory tests.

Prevalence of Listeria species and L. monocytogenes in ready-to-eat foods in the West Pomeranian region of Poland: Correlations between the contamination level, serogroups, ingredients, and producers.

Poland is one of the largest food producers in Europe, and the West Pomeranian region of Poland is a large producer of RTE food. Thus, the objective of this study was to determine the prevalence of Listeria sp. and L.

Characteristics of herring marinated in reused brines after microfiltration.

Brines after herring marinating pose a serious financial problem to the industry and natural environment. Paradoxically, the brine waste containing biological active compounds like proteases and peptides being responsible for marinade quality is discarded with sewage. Results show that the reuse of brine without filtration is not possible because of increase in the bacterial count and lipid oxidation in marinated herring.

Effect of technological factors on the activity and losses of cathepsins B, D and L during the marinating of Atlantic and Baltic herrings.

Background: This study analyzes the effect of salt and acetic acid concentration, time, temperature and fish freezing on the activity and losses of cathepsins during the marinating of Atlantic and Baltic herrings.

Results: The highest contribution to meat general proteolytic activity was found for cathepsin D-like activity. This contribution decreased during the marinating process as a result of, among other things, cathepsin losses to brine.

Distribution of Cathepsin D Activity between Lysosomes and a Soluble Fraction of Marinating Brine.

This paper is the first ever to describe the phenomenon of bimodal distribution of cathepsin D in the lysosomal and soluble fractions of brine left after herring marinating. Up to 2 times higher cathepsin D activity was observed in the lysosome fraction. Activity of cathepsin D in brine increased according to the logarithmic function during low frequency-high power ultrasounds treatment or according to the linear function after multiple freezing-thawing of brine.

Occurrence of aspartyl proteases in brine after herring marinating.

Herrings are marinated in a brine consisting of salt and acetic acid. During marinating, various nitrogen fractions diffuse from fish flesh to the brine, causing significant nutritional quality losses of the raw material. In this study, it has been demonstrated for the first time that proteases diffuse from the fish to the marinating brine.

Anthropogenic impact on the presence of L. monocytogenes in soil, fruits, and vegetables.

The aim of this study was to determine the prevalence of Listeria sp. and Listeria monocytogenes in soil samples with reference to type of fertilizers (natural and artificial) and distance from places intensively exploited by men, as well as to determine the relationship between the presence of L. monocytogenes in the soil and in fruits and vegetables.

Effect of cover brine type on the quality of meat from herring marinades.

Effects of vinegar, oil, and sour cream brines on meat quality of 4 popular cold marinades from herring were investigated in the study. Cover brine type affected the composition and nutritive value of meat as well as the sensory and microbiological quality of marinated herring. Qualitative differences resulted from cover brine penetration into meat, and from diffusion of components from meat to vinegar brine.

Losses of nitrogen fractions from herring to brine during marinating.

Fish meat is characterized by a high content of valuable nutrients. During the marinating process, however, the process of proteins diffusion and other nitrogen fractions from fish to the surrounding brine is commonly observed. It was determined that the total nitrogen loss from herring meat of industrial maturity (4-5day) amounted to 6-19% of raw material nitrogen.

Comparison of physicochemical and sensory changes in fresh and frozen herring (Clupea harrengus L.) during marinating.

Background: The influence of freezing on the changes during ripening is better described for salted fish than marinades. Therefore in the present study the effect of preliminary freezing of raw material on the ripening of carcasses and fillets marinated during 18 days at a temperature of 10 °C, in brine with 6% salt and 5% acetic acid was examined.

Results: In both cases the marinating of thawed frozen material resulted in larger mass losses and decrease of the value of meat colour parameters.