Degradation Kinetics of Anthocyanin of Traditional and Low-Sugar Blackberry Jam

The objective of this study was to monitor the stability of anthocyanin and phenolic compounds contained in two formulations of blackberry jam (traditional and low-sugar) during storage. For that purpose, jams were prepared with varying amounts of hydrocolloids and investigated as to pH, total soluble solids, water activity, total acidity, total anthocyanins and total polyphenols. In order to accompany and assess the levels of phenolic compounds and colour (L*, a* and b*) changes, the samples were stored for 180 days at two different temperatures (10 and 25 °C). The Arrhenius model was used to determine the relationship between the reaction rate (k) at the different storage temperatures, yielding activation energy values of 19 and 12 kcal/mol and Q ₁₀ values of 3.0 and 2.0 for traditional and low-sugar jams, respectively. The results show that by the end of the storage time investigated, the anthocyanin compounds had been partially degraded, with the greatest loss being observed in traditional jam stored at 25 °C. Colour stability was also lower in traditional jam as compared to the low-sugar product.     

Effect of High Hydrostatic Pressure on Physicochemical and Structural Properties of Rice Starch

Rice starch–water suspension (20%) were subjected to high hydrostatic pressure (HHP) treatment at 120, 240, 360, 480, and 600 MPa for 30 min. Polarizing light microscope, scanning electron microscopy (SEM), rapid visco analyzer (RVA), differential scanning calorimeter (DSC), and X-ray diffraction were used to investigate the physicochemical and structural changes of starch. Microscopy studies showed that the treatment of starch with HHP under 600 MPa for 30 min resulted in a complete loss of birefringence and a gel-like appearance. The treatment of starch suspension with HHP at 600 MPa resulted in a significant increase in swelling power and solubility at low temperature (50–60 °C), but opposite trends were found at high temperature (70–90 °C). The DSC analysis showed a decrease in gelatinization temperatures and gelatinization enthalpy with increase of pressure levels. RVA viscograms of starches exhibited an increase in peak, trough, and final viscosities, peak time, and pasting temperature but decrease of breakdown, setback viscosities, and pasting temperature when pressure was increased. X-ray diffraction studies showed that the HHP treatment converted rice starch that displayed the A-type X-ray patterns to the B-type-like pattern. These results showed that the treatment of rice starch in 20% starch/water suspension at a pressure of 600 MPa for 30 min led to a complete gelatinization of starch granules.     

Effects of enzymatic modification of wheat protein on the formation of pyrazines and other volatile components in the Maillard reaction

Enzymatically hydrolysed wheat gluten hydrolysate (WGH) was deamidated using glutaminase to produce deamidated wheat gluten hydrolysate (DWGH). Volatile components were analysed in WGH and DWGH thermally reacted with glucose or fructose. In the reaction system containing glucose, 19 pyrazines, 2 furans, and 5 sulphur-containing components were detected in WGH, while 34 pyrazines, 4 furans, and 7 sulphur-containing components were found in DWGH. In the system containing fructose, 24 pyrazines, 3 furans, and 6 sulphur-containing components were identified in the thermal reaction of WGH, whereas 36 pyrazines, 4 furans, and 8 sulphur-containing components were found in DWGH. The volatile components increased in DWGH, both qualitatively and quantitatively, mainly due to free ammonia released by deamidation. More volatiles were also developed in WGH and DWGH with fructose than with glucose. It was found that ammonia released from wheat protein via deamidation participated in the generation of diverse volatile components including pyrazines in the Maillard reaction.     

Relating dietary diversity and food variety scores to vegetable production and socio-economic status of women in rural Tanzania

The objective of the present study was to measure diversity in nutrition with dietary scores, and to assess their relationship to vegetable production and the socio-economic status of women in rural Tanzania. A dietary diversity score (DDS) and a food variety score (FVS) were created from data gathered with three semi-quantitative 24-h recalls performed during three non-consecutive seasons during 2006/2007. Data on vegetable production, selling and buying and socio-economic data was gathered with a semi-quantitative questionnaire. A total of 252 randomly selected women from three districts of north-eastern and central Tanzania participated. The median DDS of 6 and the mean FVS of 8.3 were low, suggesting an overall poor dietary quality, with about one third of participants having an alarmingly low DDS of only two to four food groups per day. These women consumed a very basic diet consisting mainly of cereals and vegetables. Differences among districts were pronounced while those among seasons were less distinct. The DDS and FVS were both significantly associated with ethnicity, occupation and status within the household of participants. As a more varied diet is not necessarily healthier, integration of both quantity and quality in the scores is proposed for future studies. This can be achieved, for example, by weighing food types according to their importance in the diet. As both scores are linked to the production, selling and buying of vegetables, the promotion of homestead food production may be a good way to improve dietary diversity.     

Micelle-Mediated Extraction and Flame Atomic Absorption Spectrometric Method for Determination of Trace Cobalt Ions in Beverage Samples

A new method has been developed for preconcentration of cobalt at trace levels in beverage samples using calcon carboxylic acid as chelating agent and cetyl pyridinium chloride as an auxiliary ligand and entrapped into Triton X-114 prior to its determination by flame atomic absorption spectrometry (FAAS). The main parameters affecting cloud point extraction (CPE) efficiency such as pH, concentration of the complexing agent, cationic and nonionic surfactant concentration, salt effect, the equilibrium time, and temperature were investigated and optimized. After optimization of the CPE conditions, a preconcentration factor of 60, an enhancement factor of 106, and a detection limit of 0.20 μg L⁻¹ by (R ² = 0.9978) were obtained from a calibration curve constructed in the range of 0.7–100 μg L⁻¹. The proposed preconcentration procedure was successfully applied to the determination of cobalt ions in some real samples including natural drinking water, tap water, and beer and wine samples. The accuracy and validity of the proposed CPE/FAAS method was tested by means of five repeated analysis of reference standard materials (TM-253, a low level fortified water standard for trace elements). A good agreement between analytical results (28.8 and 28.5 μg L⁻¹ with calibration curve and standard addition curve method, respectively) and certified value (27.9 μg L⁻¹) for Co (p < 0.05) were obtained and verified by means of calibration curve and standard addition curve method using CPE procedure.     

The taste of fat

For many years, fat in meats have been considered to convey quality although variations in the amounts of fat were often poorly correlated with eating qualities. The contribution of fat to taste is equally controversial, because a specific 'fat taste' perception had not been characterized. The innate attraction for fats may be due to one or more of orosensory, post-ingestive and metabolic signals. This literature review suggests that taste of lipids, particularly of oxidized PUFAs and their esters, may derive from a specific fatty acid perception mechanism in human lingual papillae. Interactions of the CD36 scavenger system with the many compounds derived from fats in cooked and processed meats offer an explanation for the variety of flavors and off-flavors found in meats. The genetic variations in the presence of receptor proteins could be one of the factors related to the differences in fat preferences in different countries and between genders.     

The effects of breed,sex, intramuscular fat and ultimate pH on pork tenderness

A study was conducted to evaluate the influence of breed and sex of animals on tenderness of pork. For evaluation, carcasses of pure breed barrows and gilts of Large White, Czech pig meat, Landrace and Duroc were used. For laboratory investigations, the samples of musculus longissimus lumborum et thoracis (20 mm thick) were taken from the same place, at the first cruciate vertebra 48 h post mortem. Seven days post mortem, the texture of heat-processed meat was measured objectively by the shear method on Instron equipped with Warner–Bratzler shear device. Meat tenderness and juiciness were also evaluated sensorially. It was observed that the tenderness of cooked meat is influenced by breed (the tenderest meat was from Duroc breed). The sex of animals has significant effect on meat tenderness too. At the same time, the effects of pH 45 minutes (pH₄₅) and 24 hours (pH₂₄) post mortem and intramuscular fat content on meat tenderness were evaluated. Correlations were found between shear force (tenderness) and intramuscular fat content and also between shear force and pH value 45 min post mortem. The shear force decreased with increasing intramuscular fat content and with increasing pH₄₅ value. Sensory evaluation of tenderness confirmed the objectively measured data.     

Microbiological,chemical and sensory assessment of mussels (<Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis>) stored under modified atmosphere packaging

Wild mussels (Mytilus galloprovincialis), were packaged aerobically under vaccum packaging(VP) and modified atmosphere packaging (MAP (50%/50% CO₂/N₂: M1, 80%/20% CO₂/N₂: M2, 65%/35% CO₂/N₂: M3), and stored at 2 ± 1 °C. Quality evaluation was carried out using microbiological, chemical and sensory analyses. Microbiological results revealed that M2 and M3 delayed microbial growth compared to M1. Of the chemical indices determined, the TVB-N and TMA-N values of M2 remained lower than the proposed acceptability limits of 35 mg N/100 g and 8 mg N/100 g, respectively, up to 8 days of storage. All of the MAP and VP mussel samples exceeded these limits after 12 days of storage. All samples retained desirable sensory characteristics during the first 8 days of storage. Based on microbiological and chemical analyses along with sensory evaluation, M2 and M3 gave a longer shelf-life compared with VP and M1. M2 gas mixture was the most effective for mussel preservation.