Effects of grilling on cholesterol oxide formation and fatty acids alterations in fish

Due to the adverse effects of the cholesterol oxidation products for the human health, the search of the occurrence and the quantification of these compounds in foods are considered of great importance. In this paper the effect of grilling in hake and sardine on cholesterol oxides formation and fatty acids alterations was investigated. The main fatty acids determined in both fishes were docosahexaenoic (DHA), oleic, eicosapentaenoic (EPA) and palmitoleic. The total lipids, fatty acids and cholesterol contents were decreased significantly (p < 0.02) after thermal treatment, with simultaneous increase of the cholesterol oxides contents. The cholesterol oxides determined in both species in the present study were: 19-hydroxycholesterol, 24(S)-hydroxycholesterol, 22(S) hydroxycholesterol, 25-hydroxycholesterol, 25(R)-hydroxycholesterol and 7-ketocolesterol. Besides the presence of the cholesterol oxides in raw fishes, there were a greater number of products resulting from the oxidation of cholesterol side chain, a fact rarely observed in foods.

Psychophysical estimation of acid intensity and determination of sweet-acid interaction in a fish paste containing glycerol

In a fish paste made with cooked Brazilian flathead (Percophis brasiliensis), glycerol (17%), sodium chloride (1.5%) and potassium sorbate (0.1%) the following acid percentages: 0.2; 0.4; 0.6; 0.8, 1 and 1.5% w/w were incorporated to determine the relationship between added acetic acid and the sensorially perceived intensity, and the effects of the combination of sweet-acid tastes. Tests for paired comparison, ranking and structured verbal scales for sweet and acid attributes and psychophysical test were carried out. There was a perceptible difference among samples for differences of 0.4 units of acid concentration. Samples indicated as sweeter by 89.47% of the judges were those containing a lesser acid concentration. A reduction in glycerol sweetness when increasing acid levels was observed. Acetic acid reduced the sweetness of glycerol and inversely glycerol reduced the acidity of acetic acid. The data obtained with the magnitude estimation test agree with Steven's law.

Application of Response Surface Methodology to study the effect of different calcium sources in fish muscle-alginate restructured products

Sodium alginate needs the presence of calcium ions to gelify. For this reason, the contribution of the calcium source in a fish muscle mince added by sodium alginate, makes gelification possible, resulting a restructured fish product. The three different calcium sources considered were: Calcium Chloride (CC); Calcium Caseinate (CCa); and Calcium lactate (CLa). Several physical properties were analyzed, including mechanical properties, colour and cooking loss. Response Surface Methodology (RSM) was used to determine the contribution of different calcium sources to a restructured fish muscle. The calcium source that modifies the system the most is CC. A combination of CC and sodium alginate weakened mechanical properties as reflected in the negative linear contribution of sodium alginate. Moreover, CC by itself increased lightness and cooking loss. The mechanical properties of restructured fish muscle elaborated were enhanced by using CCa and sodium alginate, as reflected in the negative linear contribution of sodium alginate. Also, CCa increased cooking loss. The role of CLa combined with sodium alginate was not so pronounced in the system discussed here.

Evaluation of process parameters in the industrial scale production of fish nuggets

This work reports the use of experimental design for the assessment of the effects of process parameters on the production of fish nuggets in an industrial scale environment. The effect of independent factors on the physicochemical and microbiological parameters was investigated through a full 24 experimental design. The studied factors included the temperature of fish fillet and pulp in the mixer, the temperature of the added fat, the temperature of water and the ratio of protein extraction time to emulsion time. The physicochemical analyses showed that the higher temperature of the pulp and fillet of fish, the lower the protein in the final product. Microbiological analyses revealed that the counting of Staphylococcus coagulase positive, total and thermo-tolerant coliforms were in accordance with the current legislation.

Culture alternative medium for the growth of extreme halophilic bacteria in fish products

Halotolerant or halophilic (Archaeabacteria) microorganisms can be found in salted and ripening fish products that are not affected by salt. They can be moderate or extremely halophilic bacteria. The extremely halophilic bacteria require between 15-30% of NaCl for growth. The extremely halophilic archaeobacteria may be selectively isolated in different media. The aim of this work was to determine the effectiveness of the Salt-Agar-Milk medium, a medium modified in our laboratory through the addition of MgSO4 and KCl - named SAMm, and its effect on the bacterial growth by means of comparison with other media, with and without milk, determining time of incubation and counting. Two samples of salted fish from local fish salting factories and two laboratory strains were used. The factory samples were matured anchovy and anchovy fillets in oil, and the laboratory strains were: Haloarcula spp. (proteolytic) and Halococcus spp. (non-proteolytic). The following media were alternatively used for the isolation of extremely halophilic bacteria: IRAM; Formulation of Gibbons and collaborators, Cod Milk agar, and SAMm. IRAM and Gibbons were also used enriched with milk. In the SAMm medium, there were obtained count values similar or higher than the ones of the traditional media; besides the simplicity of its elaboration, the possibility to obtain positive results two or three days earlier also added to its benefit. Consequently, it can be considered an alternative to the media traditionally used for the studied halophilic bacteria.

Acid and salt uptake during the marinatig process of Engraulis anchoita fillets influence of the solution: fish ratio and agitation

The aims of this research were to determine the effect of different conditions of the marination stage on the salt and acid uptake, immersion time, and sensorial characteristics during the marinating process of anchovy (Engraulis anchoita). Different solution:fish ratios and the agitation effect during this stage were analyzed. The ratios used were: 0.77:1, 3:1 and 10:1 (with and without agitation). An increase of marinating solution:fish ratio causes a higher speed of acid and salt penetration The product obtained with the 10:1 ratio had a dry and fibrous texture and a slightly salty taste. Salt concentration was statistically significantly lower (p < 0.01) in the samples with agitation. Agitation did not influence the acid uptake, and the salt penetration speed decreased, but rancidity was detected in this product. The ratio 3:1 decreases the marinating time without damaging sensory attributes and can be used in the fish marinating process.

Fish crackers development from minced fish and starch: an innovative approach to a traditional product

This study aimed to develop sensory acceptable, high nutritional value fish crackers that could be kept at room temperature for 180 days. Minced fish of different low-value species was the raw material employed to produce two types of fish crackers: a) the traditional keropok cracker, which was expanded by deep frying; and b) a low-fat fish cracker, expanded by microwave cooking. The protein content of the fried fish crackers (FFCs) and that of the microwaved fish crackers (MFCs) were high (10.86 and 14.70%, respectively). The essential amino acid contents of the two types of fish cracker were above the FAO requirements for adults, and the lysine content was above the requirements for children. Sensory analysis, performed by adult panelists, resulted in a general level of acceptability of 90% for the MFCs and of 97% for the FFCs. Vacuum packaging maintained microbiological and physicochemical properties for a storage period of 180 days at room temperature.

Application of exploratory factor analysis to assess fish consumption in a university community

The objective of this research was to use the technique of Exploratory Factor Analysis (EFA) for the adequacy of a tool for the assessment of fish consumption and the characteristics involved in this process. Data were collected during a campaign to encourage fish consumption in Brazil with the voluntarily participation of members of a university community. An assessment instrument consisting of multiple-choice questions and a five-point Likert scale was designed and used to measure the importance of certain attributes that influence the choice and consumption of fish. This study sample was composed of of 224 individuals, the majority were women (65.6%). With regard to the frequency of fish consumption, 37.67% of the volunteers interviewed said they consume the product two or three times a month, and 29.6% once a week. The Exploratory Factor Analysis (EFA) was used to group the variables; the extraction was made using the principal components and the rotation using the Quartimax method. The results show clusters in two main constructs, quality and consumption with Cronbach Alpha coefficients of 0.75 and 0.69, respectively, indicating good internal consistency.

Raw-appearing Restructured fish models made with Sodium alginate or Microbial transglutaminase and effect of chilled storage

Restructuring by adding Sodium Alginate or Microbial Transglutaminase (MTGase) using cold gelation technology make it possible to obtain many different raw products from minced and/or chopped fish muscle that are suitable for being used as the basis of new restructured products with different physicochemical properties and even different compositions. Special consideration must be given to their shelf-life and the changes that may take place during chilling, both in visual appearance and physicochemical properties. After chilled storage, the restructured models made with different muscular particle size and composition at low temperature (5 °C), it was observed that microbial growth limited the shelf-life to 7-14 days. Mechanical properties increased (p < 0.05) during that time, and higher values were observed in samples elaborated by joining small muscle particle size than in those elaborated by homogenization. There was no clear increase in the cooking yield and purge loss, and no significant colour change (p > 0.05) was detected during storage.

Relationship between the price of fish and its quality attributes: a study within a community at the University of São Paulo, Brazil

The aim of this study was to evaluate the associations between the products' market price and attributes related to fish purchase and consumption within a university community in Brazil. A structured questionnaire consisting of a five-point Likert scale was used. It was previously tested and made available to the university community via the Internet. The sample comprised 1966 voluntaries including university students and faculty and staff members. A descriptive analysis of data was performed using Spearman's correlation analysis. The results showed that the majority of the respondents (56%) consume fish at home; some consume fish at restaurants (39%), and 5% at family or friends' houses, reinforcing the idea that variables such as culture and reference groups are fundamental determinants of purchase and consumption behavior. It was identified a significant (p < 0.001) and very strong correlation between the attributes price and nutritional value (r = 0.92); price and availability at the usual places of purchase (r = 0.92); price and packaging (r = 0.92); price and brand name (r = 0.91); and price and of the Federal Inspection stamp (r = 0.91) and a low positive correlation (p < 0.001) between the price variable and the initiative for fish traceability (r = 0.16). This study demonstrated that the price of fish is associated with the quality of the product and the attributes related to it such as packaging, nutritional value, and availability of the product in the market.

Preliminary studies on nutritive and organoleptic properties in processed fish fillets obtained from Iran

The effects of boiling, frying, and roasting methods on nutrients and properties some of marine fishes were studies. AOAC official methods were used for the analyses of the samples. Frying reduced the protein content of Nemipterus japonicas, while roasting reduced the protein content of Carangoides malabaricus and Saurida undosquamis. Fresh and fried C. malabaricus had 71.2% and 57.05% protein content, respectively, while N. japonicas had 57.39% and 47.51%, respectively. The highest oil content in C.malabaricus was 16.80%, followed by N.japonicus 12.80%; while the lowest oil content in S.undosquamis was 5.88%. N.japonicusis protein content reduced with frying. Some cooking methods used in the processing can have an effect on of fish nutrient composition. The texture of fried and boiled fish fillets significantly differ from that of the roasted fillets (p<0.05).

Designing and validating the methodology for the Internet assessment of fish consumption at a university setting

Assessing fish consumption is complex and involves several factors; however, the use of questionnaires in surveys and the use of the Internet as tool to collect data have been considered promising approaches. Therefore, the objective of this research was to design a data collection technique using a questionnaire to assess fish consumption by making it available on a specific home page on the Internet. A bibliographical survey or review was carried out to identify the features of the instrument, and therefore pre-tests were conducted with previous instruments, followed by the Focus Group technique. Specialists then performed an analysis and conducted an online pre-test. Multivariate data analysis was applied using the SmartPLS software. The results indicate that 1.966 participants belonging to the University of São Paulo (USP) community participated in the test, and after the exclusion of some variables, a statistically significant results were obtained. The final constructs comprised consumption, quality, and general characteristics. The instrument consisted of behavioral statements in a 5-point Likert scale and multiple-choice questions. The Cronbach's alpha reliability coefficient was 0.66 for general characteristics, 0.98 for quality, and 0.91 for consumption, which indicate good reliability of the instrument. In conclusion, the results proved that the Internet assessment is efficient. The instrument of analysis allowed us to better understand the process of buying and consuming fish in the country, and it can be used as base for further research.

Effects of filtration methods on the neutralization yield of crude marine fish oil

The evaluation of filtration methods on the yield and oleochemicals characteristics on the crude fish oil from the soapstock of marine fish for purposes of nutrition has been conducted in this work. The analytical properties of the crude and the neutralized oil with three excesses of sodium hydroxide (NaOH, 20%, 40% and 60%) were carried out on two different ways with organza and the “glass wool”. The neutralization of the oil brought about a notable improvement in the analytical properties of the oil. Thus, it leads to a high quality fish oil in terms of taste, colour, odours, shelf life and market value. Based on the improved characteristics of the oil, it could be suitable for applications in pharmaceutical and food industries.

Characterization of a hydrolyzed oil obtained from fish waste for nutraceutical application

The fish industry generates high volume of waste from fish oil that can have the extraction of its lipids used as nutraceuticals and foods. The objective of this study was to produce unsaturated fatty acids from industrialized fish oil by means of a differentiated hydrolysis process. The samples used were crude fish oil obtained from Campestre industry and characterized through physical-chemical parameters, according to AOCS: acidity, peroxide, saponification, iodine and percentage of free fatty acids and also obtained the fatty acid profile through derivatization method for gas chromatography. The results obtained for the oleochemical indices for refined oil were similar to the data found on the literature. The content of polyunsaturated fatty acids (PUFA) was found of 32,78%, with 9,12% of docosahexaenoic (DHA) and 10,36% of eicosapentaenoic (EPA), regarding monounsaturated fatty acids (MUFA) content was of 30,59% in the hydrolyzed fish oil in relation to refined (20,06%). Thus, it can be concluded that the hydrolysis process used for oils from fish-waste was satisfactory on the production of absolute yield of lipids in the process and significant preservation on the percentages of EPA and DHA, interesting on the production of nutraceuticals and nutrition of aquatic animals, including shrimp in captivity.

Fish consumption preferences and factors influencing it

Fish consumption preferences are affected by individuals’ socioeconomic characteristics. The aims of the present paper were (i) to obtain information on fish consumption level and frequency; (ii) to investigate the associations between the socioeconomic characteristics of consumers and their preferences; and (iii) to examine the influence of determinants on fish consumption. Data were gathered through a questionnaire completed by a total of 127 randomly selected individuals from different socioeconomic backgrounds from the Antakya, Turkey. The average consumption was found to be 2.98 kg/person/year for fish. Anchovies, gilt-head sea bream, and sea bass were reported as the most consumed three species, respectively. Significant differences in fish consumption were found among age groups, gender groups, and education groups, as well as between marital statuses. A majority of the consumers eat fish once a month throughout the year or only during the winter months. Fish consumption level and frequency were significantly positively correlated with education (p<0.01), income (p<0.05) and total meat consumption (p<0.01). The stepwise multiple regression model explained 41.7% (p<0.01) of the total variance for fish consumption. The amount and frequency of the consumption in the region, which is very far below the world and Turkey average especially for lower socioeconomic groups and for less-consumed fish species, can be increased by certain policies, such as training, advertising and different marketing strategies. Moreover, consumption should be distributed equally throughout the year instead of consuming only in certain seasons.