a b s t r a c tThe biological cause of broiler PSE meat seems to be an excessive release of Ca 2+ , promoted by a genetic mutation of ryanodine receptors located in the sarcoplasmic reticulum of skeletal muscle cells. Excessive Ca 2+ , associated with protein denaturation in meat, enhances protease activity and influences the functional properties of PSE meat. Twenty-four-hour post-mortem Pectoralis major m. samples exhibited lower values for pH, water-holding capacity, and shear force than did control samples, in contrast to colour (L * ) and cooking loss values. Protease activity, measured as myofibril fragmentation index, presented higher values in PSE meat than in control samples. Ultrastructural examination revealed shrinking and depolymerisation of myofilaments and Z-lines disorganisation within the sarcomere in PSE meat. Intense calpain activity was also observed, indicating that the process may initiate at the filaments, because of protein denaturation, and spread through Z-lines, resulting in the collapse of the sarcomere structure.

Pequi fruit (Caryocar brasiliense Camb) is considered important since its pulp has a high content of oil and carotenoids. The oil's triacylglycerols (TAGs) contain mainly oleic (~57%) and palmitic (~36%) fatty acids, distributed primarily among POO, POP/PPO, and OOO TAGs. It displays a tendency to fractionate upon storage and has a relatively low melting temperature (SFC of 4% at 25°C). Pequi oil was modified through chemical interesterification, which increased the PPP content to ~6%. This caused a flattening in the SFC-temperature profile, raising the end of melt temperature significantly (SFC of 4% at 39°C). The interesterified oil does not fractionate and is thermally stable up to 40°C, with an SFC-temperature profile resembling that of roll-in shortening (SFC of 31% at 16°C) despite containing high amounts of oleic acid. Crystallization and melting behavior changed. Crystal packing became more disorganized as evidenced by a significant decrease in crystalline domain size in the [001] direction from 42.3 nm to 32.1 nm. Polymorphism remained of the triclinic (β) subcell type but polytypism changed from the 3L to the 2L type. Polarized light microscopy demonstrated that interesterification dramatically decreased crystal size, consistent with a higher rate of nucleation in the material. Moreover, the dramatic improvement in physical stability and functionality was not accompanied by a significant decrease in total carotenoid content (~390 mg/kg).

RESUMO Sementes de maracujá foram submetidas à prensagem sob diferentes taxas de alimentação (1,2 a 3,0kgh -1 ) com o objetivo de avaliar o impacto desta variação no rendimento do processo

ABSTRACT

The seed oil of Carapa guianensis (Aublet), a tree from the Meliaceae family commonly known as andiroba, is widely used in Brazilian traditional medicine because of its multiple curative properties against fever and rheumatism and as an anti-inflammatory agent, antibacterial agent, and insect repellant. Since there is no consensus on the best way to obtain the C. guianensis oil and due to its ethnomedicinal properties, the aim of the present research was to evaluate the chemical composition, free-radical scavenging activity, and mutagenic and genotoxicity properties of three C. guianensis oils obtained by different extraction methods. The phenolic contents were evaluated by spectrophotometry. Oil 1 was obtained by pressing the dried seeds at room temperature; oil 2 was obtained by autoclaving, drying, and pressing; oil 3 was obtained by Soxhlet extraction at 30–60°C using petroleum ether. The oil from each process presented differential yields, physicochemical properties, and phenolic contents. Oil 1 showed a higher scavenging activity against the DPPH radical when compared to oils 2 and 3, suggesting a significant antioxidant activity. All oils were shown to be cytotoxic to bacteria and to CHO-K1 and RAW264.7 cells. At noncytotoxic concentrations, oil 2 presented mutagenicity to Salmonella enterica serovar Typhimurium and induced micronuclei in both cell types. Under the same conditions, oil 3 also induced micronucleus formation. However, the present data demonstrated that oil 1, extracted without using high temperatures, was the safest for use as compared to the other two oils, not showing mutagenicity or micronucleus induction.