Elisabete Maria Macedo Viegas

Quality of sausage elaborated using minced Nile Tilapia submmitted to cold storage

ABSTRACT: Filleting yield of Nile tilapia Oreochromis niloticus (L.) is low (30%) and generates large amountof wastes that may turn into environmental and economic problem. However, these wastes can be used for theextraction of minced fish (MF) which can be used in the preparation of sausages. The objective of this studywas to assess the quality of sausages prepared with 0, 20, 40, 60, 80 and 100% of MF from Nile tilapia filletingwaste during storage at 0±0.3oC. Alterations in the instrumental color (L*, a* and b*), lipid oxidation(TBARS), total volatile nitrogenous bases (TVB-N), pH, microbiological condition (pathogenic bacteria andaerobic psychrotrophic bacteria), and sensory attributes (color, odor, flavor, texture and overall acceptability)were evaluated for up to 40 days. The addition of MF to sausages increased TBARS values and decreases TVB-N, L*, a* and b* values. Acceptability of color attribute decreased with increasing MF; best flavor, texture andoverall acceptability scores were registered for sausages containing 40 and 60% MF; best odor was registeredfor 100% MF. Pathogenic microorganisms were not detected, but decrease in pH and proliferation of aerobicpsychrotrophic bacteria which, however, did not compromise sensory evaluation of sausages were registeredthroughout storage. Sausages prepared with MF from tilapia filleting waste have a shelf-life of 40 days whenstored at 0±0.3oC, and the maximum recommended MF inclusion to maintain good sensory quality is 60%.Key words: Fish sausage, lipid oxidation, filleting waste, shelf-life, sensory acceptability

Elaboration of sausage using minced fish of Nile tilapia filleting waste

ABSTRACT The objective of this study was to evaluate the inclusion of minced fish (MF) (0, 20, 40, 60, 80 and 100%), obtained from Nile tilapia filleting waste, in sausage and determine their physicochemical, nutritional and sensory properties. The sausages showed a decrease in protein and increase in fat content with increasing inclusion of MF. The nutritional quality of the products was high, with digestibility over 85%. The parameters of texture instrumental and yellow color (b*) decreased with the increasing inclusion of MF. The sensory evaluation of the color showed that the maximum level of inclusion of MF was not well accepted by the panelists. The sausage with the best acceptance for the flavor attribute was those with 60% of MF. The results showed good nutritional quality of sausages utilizing MF of Nile tilapia filleting waste and according to the sensory evaluation, the maximum level of inclusion should not exceed 60%. Key words: Oreochromis niloticus , sausage, nutritional quality, minced fish, sensory acceptance, texture

Efeito do peso de tilápia no nilo (Oreochromis niloticus) sobre e rendimento e a qualidade de seus filés defumados com e sem pele

The objective of this study was to evaluate the effect of different weights of Nile tilapia (Oreochromis niloticus) on yield and quality of smoked and in natura fillets, with and without skin. One hundred tilapias, divided into three weight classes (C1=500-600g; C2=601-700g; C3=701-800g) were used. Two fillet types, with skin and without skin were removed from each sample, salted and hot smoked. Weight affected yield of in natura (C1 = 38.54; C2 = 40.23 e C3 = 40.47%) and smoked fillets (C1 = 22.97; C2 = 24.51 e C3 = 24.68%), and in natura fillet mass index (C1 = 36.69; C2 = 39.45 e C3 = 41.18 g.cm-2). The latter was higher in classes C2 and C3. Fillet with skin had a higher (p<0.05) water activity (0.99) rate than that of fillet without skin (0.98). Salt rate was higher (p<0.01) in smoked fillets than in natura ones. It was observed higher salt levels in the C1 skinless class. With the exception of a* and b* in natura fillet, no difference was reported in color. Smoked fillets from C3 class fish were more acceptable by judges. In larger fish the equation Y= -21.52 + 0.16034X (r=0.80), where X is the weight of fish, may be employed to calculate smoked fillets size, while Y= -17.74 + 0.14198X (r=0.81) for smoked skin-less fillets. Regardless of skin presence, the smoked fillets from largest fishes (C2 and C3 classes) yielded better results (approximately 24%), as well as in the sensorial analysis, related to salt ratio and general acceptance. Fillets in natura showed low values to a* and b*. Weight classes and skin presence in the fillets had no influence in composition, but caused a variation in their area and thickness. The largest fillets were with skin, belonging to class C3.

Defumação da tilápia do Nilo (Oreochromis niloticus) inteira eviscerada e filé: aspectos referentes às características organolépticas, composição centesimal e perdas ocorridas no processamento

The objective of the experiment was to evaluate the smoking process effect of whole eviscerated and fillet of Nile tilapia on the organoleptic characteristics (appearance, aroma, color, flavor, texture, salt content and general acceptance), percent weight loss (PP) and proximate composition. FP1 (whole eviscerated fish, 5 hour smoking) and FP2 (fillet, 4 hour smoking) were compared. Scaled, eviscerated fish, FP1 and fillets cut by only one person, FP2 were submitted to brine (30%) and smoking process. Average yield for FP1 and FP2 was 63.98% and 27.11%, respectively. Average loss weight during smoking for fillet (31.33%) was higher, when compared to whole fish (27.04%). Sensorial analysis showed that whole fish was more accepted, regarding flavor and salt content; however, aroma, color and texture were not different between whole fish and fillet. Smoking process reduced moisture and increased crude protein, lipid and ash contents. Losses were higher for fillet, which presented higher crude protein and lower lipid contents compared to whole fish. It was also verified that fillet flavor can be improved by correcting the brine step.

Alterações na qualidade do camarão de água doce Macrobrachium rosenbergii durante estocagem em gelo

Due the scarcity of studies about post-harvest conservation of Macrobrachium rosenbergii and few knowledge in this topic, the aim of this work was to evaluate it shelf-life when stored as a whole in ice during 10 days. Two conditions were compared: with direct ice contact and without ice contact. In both treatments were observed an increase (P<0,05) in Non-Protein Nitrogen, Total Volatile Base Nitrogen, Thiobarbituric Acid Reactive Substances and pH values. No faecal coliforms were observed in the prawn muscles during the storage. The score of total coliforms and psychrotrophic counting that was present in the storage period didn´t exceed the law limits allowed for consumption. There was degradation in flavour and odour attributes for both treatments during the storage. Analysis of tactile and oral texture showed a fast and significant degradation in both treatments in the first days of storage, and the same occurred with the instrumental compression force tests. We concluded the Macrobrachium rosenbergii could be consumed until the 4th storage day, either if kept in direct ice contact or packed in polyethylene bags.

Evaluation of Physicochemical and Sensory Properties of Sausages Made with Washed and Unwashed Mince from Nile Tilapia By-products

This study evaluates the effects of inclusion level (60 to 100%) and washing cycles (0 to 2) of minced fish from Nile tilapia fillet by-products on proximate composition, mineral contents, color, hardness, and sensory acceptance of sausages. A complete 22 factorial experimental design was used. Regression models for protein, fat, moisture, minerals, color, and hardness were developed. The optimum combinations for the independent variables are sausages made with 100% non-washed minced fish, which represents a better use of by-products without generating washing residues, leading to less expensive sausage with higher nutritional value.

Shelf-Life of Tail Meat of the Giant River Prawn, Macrobrachium rosenbergii, Stored on Ice

ABSTRACT The objective of this study was to evaluate the shelf-life of peeled giant river prawn Macrobrachium rosenbergii stored directly in contact with ice (DCI), and without direct contact with ice (WCI). The prawns from DCI treatment showed an intense leaching of non-protein nitrogen (NPN) and total volatile bases nitrogen (TVB-N), thus suggesting that NPN or TVB-N should not be used as freshness indicators of peeled tails stored directly in contact with ice. Loss of flavor and a quick texture tactile decrease with time occurred in both treatments. The shelf-life of peeled tails prepared from M. rosenbergii was 7 days for DCI and 10 days for WCI.

How stunning methods affect the quality of Nile tilapia meat

Nile tilapia, Oreochromis niloticus, is one of the most cultivated fish species in Brazil. However, few studies evaluate how the stunning methods affect the meat quality of this fish. This study evaluates how both stunning methods, iced water and CO2 narcosis, affect the quality of tilapia meat that was stored refrigerated in ice (4°C) for up to 26 days. Tilapia stunned by CO2 narcosis showed less stress compared to iced water, which was evidenced by the higher ATP, and better meat color as well, evidenced by higher lightness (L*) and lower redness (a*) values. After sensorial analysis, fish were classified as extra-fresh during the first 2 days of storage; as fresh from day 3 to day 14, not fresh from day 15 to day 23; and as spoiled from day 23 onwards. Stunning of tilapia by CO2 narcosis can be an alternative to the traditional method of desensitization (iced water) used in Brazil.

Estabilidade em armazenamento da carne de tilápia-do-nilo mecanicamente separada, lavada, adicionada de conservantes e congelada

The objective of this work was to evaluate the influence of the washing process and of the addition of sodium erythorbate and sodium tripolyphosphate on the stability of mechanically separated meat (MSM), obtained from Nile tilapia (Oreochromis niloticus) filleting waste. Four treatments were evaluated, in triplicate: washed or nonwashed MSM, stored with or without the addition of preservatives, during 180 day storage at ‑18oC. To evaluate stability, microbiological, nonprotein nitrogen, volatile basic nitrogen, lipid oxidation by Tbars index, pH value, and drip loss analyses were carried out. The washing process increased moisture content and decreased crude protein, fat, and ash contents in MSM, as well as the levels of nonprotein nitrogen, volatile basic nitrogen, and lipid oxidation after washing. During storage, no differences were detected for nonprotein nitrogen levels, pH values, and drip loss, but there was an increase in volatile basic nitrogen values. The washing process favors tilapia MSM stability, and the addition of sodium tripolyphosphate and erythorbate reduces lipid oxidation of the unwashed product.

Changes during chilled storage of whole tilapia and short-term frozen storage of tilapia fillets

This study evaluated the physicochemical changes in Nile tilapia (n = 82, 373.71 ± 61.91 g) refrigerated for up to 92 h and in the frozen fillets. The tilapias were captured with nets, slaughtered by ice and water shock (1:1) in a temperature of approximately 2°C for 30 min, and stored refrigerated at 4°C in polystyrene boxes containing ice. The fish were filleted, and filets were weighed and frozen. The drip loss and protein were determined after 23 days of frozen storage. After 4 h of storage, all fish were in full rigor mortis. The pH of the muscles decreased for up to 45 h of the storage period. The fillets obtained from tilapia stored for more than 72 h lost more weight and protein. Thus, the filleting or processing of tilapia should be done before 72 h of cold storage, since deterioration of the fish starts to occur after this period.This study evaluated the physicochemical changes in Nile tilapia (n = 82, 373.71 ± 61.91 g) refrigerated for up to 92 h and in the frozen fillets. The tilapias were captured with nets, slaughtered by ice and water shock (1:1) in a temperature of approximately 2°C for 30 min, and stored refrigerated at 4°C in polystyrene boxes containing ice. The fish were filleted, and filets were weighed and frozen. The drip loss and protein were determined after 23 days of frozen storage. After 4 h of storage, all fish were in full rigor mortis. The pH of the muscles decreased for up to 45 h of the storage period. The fillets obtained from tilapia stored for more than 72 h lost more weight and protein. Thus, the filleting or processing of tilapia should be done before 72 h of cold storage, since deterioration of the fish starts to occur after this period.