Lipid oxidation and fishy odour development in protein hydrolysate from Nile tilapia (Oreochromis niloticus) muscle as affected by freshness and antioxidants

Lipid oxidation and fishy odour development in protein hydrolysate from fresh and ice-stored Nile tilapia (Oreochromis niloticus) were investigated. During iced storage of 18 days, heme iron content decreased with a concomitant increase in non-heme iron content (P < 0.05). Peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) values increased. Phospholipid content decreased with a corresponding increase in free fatty acid content. The results suggested that lipid hydrolysis and oxidation took place during storage. When protein hydrolysates were produced from fresh and 18 days ice-stored Nile tilapia muscle, higher lipid oxidation and fishy odour/flavour along with higher amount volatile compounds were obtained in hydrolysate for unfresh sample (P < 0.05). However, the addition of mixed antioxidants during hydrolysis process markedly lowered lipid oxidation, b^∗, ΔC^∗, ΔE^∗ values, fishy odour/flavour as well as the formation of volatile compounds in the resulting hydrolysates prepared from both fresh and unfresh samples. Therefore, hydrolysate from Nile tilapia muscle with reduced fishy odour and lighter colour could be prepared by using fresh fish and incorporation of mixed antioxidants during hydrolysis.     

Compositions,functional properties and antioxidative activity of protein hydrolysates prepared from round scad (Decapterus maruadsi)

Composition, functional properties and antioxidative activity of a protein hydrolysate prepared from defatted round scad (Decapterus maruadsi) mince, using Flavourzyme, with a degree of hydrolysis (DH) of 60%, were determined. The protein hydrolysate had a high protein content (48.0%) and a high ash content (24.56%). It was brownish yellow in colour (L^∗ = 58.00, a^∗ = 8.38, b^∗ = 28.32). The protein hydrolysate contained a high amount of essential amino acids (48.04%) and had arginine and lysine as the dominant amino acids. Na⁺ was the predominant mineral in the hydrolysate. The protein hydrolysate had an excellent solubility (99%) and possessed interfacial properties, which were governed by their concentrations. The emulsifying activity index of the protein hydrolysate decreased with increasing concentration (p < 0.05). Conversely, the foaming abilities increased as the hydrolysate concentrations increased (p < 0.05). During storage at 25 °C and 4 °C for 6 weeks, the antioxidative activities and the solubility of round scad protein hydrolysate slightly decreased (p < 0.05). Yellowness (b^∗-value) of the protein hydrolysate became more intense as the storage time increased but the rate of increase was more pronounced at 25 °C than at 4 °C.     

Roles of lipid oxidation and pH on properties and yellow discolouration during storage of film from red tilapia (Oreochromis niloticus) muscle protein

Protein-based films prepared from red tilapia (Oreochromis niloticus) washed and unwashed mince solubilised at pH 3 and 11 were prepared and characterised. Tensile strength (TS) of films from washed mince was greater than that of films prepared from unwashed mince for both pH used (P < 0.05). TS of films prepared at pH 3 was higher than that of films prepared at pH 11 for both of washed and unwashed mince (P < 0.05). Film from washed mince with pH 3 showed the highest TS, while that from unwashed mince with pH 11 had the lowest TS with the highest elongation at break (EAB) (P < 0.05). Films from washed mince had the lower value of thiobarbituric acid reactive substances (TBARS) than did those from unwashed counterpart, regardless of pH used. Nevertheless, TBARS was much higher in films prepared at acidic pH, compared with those prepared at alkaline pH. During storage of 20 days at room temperature, films became yellowish as evidenced by the increases in b^∗ and ΔE^∗-values. Films prepared at pH 11 showed the higher b^∗ and ΔE^∗-values than did those prepared at pH 3, especially for those from unwashed mince. However, films prepared from washed mince at pH 3 showed higher b^∗ and ΔE^∗-values than did those prepared at pH 11 (P < 0.05). Films generally had the increase in TS but the decreases in water vapour permeability (WVP), film solubility and protein solubility after 20 days of storage (P < 0.05). Therefore, lipid oxidation more likely played a role in yellow discolouration of fish muscle protein film, mainly by providing the carbonyl groups involved in Maillard reaction, while pH regulated the rate of reaction.     

Effect of tannic acid and kiam wood extract on lipid oxidation and textural properties of fish emulsion sausages during refrigerated storage

Effect of tannic acid (0.02% and 0.04%) and ethanolic kiam wood extract (EKWE) (0.04% and 0.08%) on lipid oxidation and textural properties of fish emulsion sausages during 20 days of refrigerated storage was investigated. Control samples (C) had the highest peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) value up to day 16 and 8 of storage, respectively. With the addition of tannic acid and EKWE, PV and TBARS values in the sausages were retarded effectively, compared to the control (P < 0.05), especially when the tannic acid and EKWE at higher level were used. At the same level, EKWE showed the lower ability in retarding the lipid oxidation, in comparison with tannic acid. Tannic acid at both levels (0.02% and 0.04%) was also effective in retarding the formation of fishy odour in the samples throughout the storage, compared to the control and EKWE treated samples (P < 0.05). Both tannic acid and EKWE had no detrimental effect on the sensory attributes of sausages. However, EKWE treated sample had lower L^∗ and higher a^∗ and ΔE^∗ values, compared to the control samples (P < 0.05). After 20 days of storage, the sample added with 0.04% tannic acid had higher hardness, gumminess and chewiness, compared with others (P < 0.05). Samples added with 0.04% tannic acid also displayed more compact structure with no visible voids. Furthermore, oil droplets with smaller size were dispersed more uniformly, compared to others. Thus, tannic acid (0.02% and 0.04%) and EKWE (0.08%) were effective in retarding lipid oxidation and fishy odour development as well as could maintain the textural properties of fish emulsion sausages during the refrigerated storage of 20 days.     

The antioxidative properties of mustard leaf (Brassica juncea) kimchi extracts on refrigerated raw ground pork meat against lipid oxidation

The efficacy of varying concentration of mustard leaf kimchi ethanolic extracts (MK) in retarding oxidative rancidity was tested with raw ground pork. Freshly ground pork meat was assigned to one of the following five treatments: control (no antioxidants); AC-0.02 (0.02% ascorbic acid); MK-0.05, 0.1, and 0.2 (0.05%, 0.1% and 0.2% MK, respectively). The pH of the samples decreased and the TBARS values and free fatty acids (%) increased considerably (P < 0.05) during storage. The total bacterial count was lower in MK-0.1 and MK-0.2 than the control during storage. The internal L∗ value and a∗ value decreased (P < 0.05) with the addition of MK. The internal b∗ value of MK treatments were higher (P < 0.05) than that for the control and increased incrementally with MK concentration. The TBARS values and free fatty acids (%) of MK-0.02 was lowest among the treatments. The peroxide value of the control increased until 7 days and reached the maximum value at a certain storage time and decreased thereafter. In the other treatments it increased. All treatments had lower concentration of conjugated dienes (P < 0.05) compared to the control sample, after the first day. Mustard leaf kimchi ethanolic extracts exhibited a protective effect against lipid oxidation in raw ground pork.     

Fishmeal-based diet decreases the redness of sunshine bass (Morone chrysops × Morone saxatilis) fillets

The objectives of the present study were to determine the effects of feeding a fishmeal-based diet on color attributes and lipid oxidation in sunshine bass (Morone chrysops × Morone saxatilis) fillets during retail display. A balanced diet containing 30 percent fishmeal (FM) or a diet containing poultry byproduct meal as a complete replacement of fishmeal (PB) was fed to sunshine bass for fifteen months. Harvested fish were filleted, overwrapped with polyvinyl chloride film and stored at 2 °C (REF) or over ice (ICE), under an illuminated retail display. Samples (n = 6) were analyzed after 0, 3, 6, or 9 d storage for color attributes (CIE L^∗, a^∗, b^∗, hue angle and chroma), thiobarbituric acid-reactive substances (TBARS), and pH. TBARS and pH increased (P < 0.05) during storage, indicating progress in lipid oxidation and protein changes. FM fillets demonstrated lower (P < 0.05) a^∗ (redness) value and greater (P < 0.05) hue angle than PB fillets. Since consumer acceptance of sunshine bass is dependant upon its white flesh, fishmeal supplementation could be used as a dietary strategy to improve fish marketability.     

Oxidative changes of fresh loin from pig,caused by dietary conjugated linoleic acid and monounsaturated fatty acids,during refrigerated storage

Three levels (0%, 1% and 2%) of a conjugated linoleic acid enriched oil (CLA) were combined with two levels of monounsaturated fatty acids (MUFA) (19% and 39% average) for pig feeding. Changes in instrumental colour, lipid oxidation (thiobarbituric acid reactive substances, TBARS) and volatile profile of fresh loin chops, as affected by dietary CLA, MUFA and CLA × MUFA, were studied throughout 7 days of refrigerated storage. Lightness (L∗) evolution was conditioned by dietary CLA, whereas changes in redness (a∗) and yellowness (b∗) were unaffected by dietary supplements. Dietary CLA at 2% led to higher TBARS values of loin chops at day 7 of refrigerated storage (p < 0.05), while MUFA supplementation and CLA × MUFA interaction did not affect lipid oxidation. Dietary CLA, MUFA or CLA × MUFA did not affect most volatile compounds of loin chops after 7 days of storage.     

Use of viscera extract from hybrid catfish (Clarias macrocephalus × Clarias gariepinus) for the production of protein hydrolysate from toothed ponyfish (Gazza minuta) muscle

Proteolytic activity of viscera extract from hybrid catfish (Clarias macrocephalus × Clarias gariepinus) was studied. The optimal pH and temperature were 9.0 and 50 °C, respectively, when toothed ponyfish (Gazza minuta) muscle was used as a substrate. When viscera extract from hybrid catfish was used for the production of protein hydrolysate from toothed ponyfish muscle, extract concentration, reaction time, and fish muscle/buffer ratio affected the hydrolysis and nitrogen recovery (NR) (p < 0.05). Optimum conditions for toothed ponyfish muscle hydrolysis were 3.5% hybrid catfish viscera extract, 15 min reaction time and fish muscle/buffer ratio of 1:3 (w/v). High correlation between the degree of hydrolysis (DH) and NR (R² = 0.974) was observed. Freeze-dried hydrolysate had a high protein content (89.02%, dry weight basis) and it was brownish yellow in colour (L^∗ = 63.67, a^∗ = 6.33, b^∗ = 22.41). The protein hydrolysate contained a high amount of essential amino acids (48.22%) and had arginine and lysine as the dominant amino acids.     

Effect of irradiation on properties and storage stability of Som-fug produced from bigeye snapper

Effects of irradiation at different doses (0, 2 and 6 kilogray (kGy)) on the microbiological, chemical and physical properties of Som-fug, a Thai fermented fish mince, were investigated. Lactic acid bacteria (LAB), yeast and mould counts in samples irradiated at 6 kGy were not detectable throughout the storage of 30 days at 4 °C, whereas no growth was found in the sample irradiated at 2 kGy within the first 10 days. Generally, greater carbonyl contents of lipid and protein, as well as thiobarbituric acid-reactive substances (TBARS), were noticeable in the irradiated samples, than in the non-irradiated sample (p < 0.05). The carbonyl contents and TBARS increased with increasing storage time and the rate of increase was more pronounced in samples irradiated at higher dose (p < 0.05). With increasing storage time, Som-fug irradiated at 6 kGy showed greater decreases in hardness, adhesiveness, springiness and cohesiveness, than did non-irradiated samples and those irradiated at 2 kGy (p < 0.05). L^∗ value of all samples decreased, whereas a^∗ and b^∗ values increased throughout storage (p < 0.05). Lower acceptance in all attributes was observed in the samples irradiated at 6 kGy, than in other samples, particularly when storage time increased (p < 0.05). However, samples irradiated at 2 kGy showed no changes in acceptability within 20 days. The results revealed that irradiation at high dose (6 kGy) might induce lipid and protein oxidation, though the growth of microorganisms was inhibited. Therefore, the irradiation at low dose (2 kGy) could be used to control the overfermentation of Som-fug up to 20 days at 4 °C without adverse effects on quality and acceptability.     

Effect of iced storage of bigeye snapper (Priacanthus tayenus) on the chemical composition,properties and acceptability of Som-fug,a fermented Thai fish mince

The effect of iced storage of bigeye snapper (Priacanthus tayenus) on the chemical composition, properties and acceptability of Som-fug was investigated. During 15 days of iced storage, total volatile base (TVB), trimethylamine (TMA) and TCA-soluble peptide contents as well as thiobarbituric reactive substances (TBARS) of fish muscle increased continuously after 3 days of storage (p < 0.05). It was suggested that deterioration, protein degradation and lipid oxidation proceeded with increasing storage time. Som-fug prepared from surimi of bigeye snapper stored in ice for different times had similar pH, acidity and lactic acid bacteria count at the end of the fermentation (30 °C, 48 h). Generally, higher content of TCA-soluble peptides and higher TBARS were found in fermented Som-fug produced from bigeye snapper stored in ice for a longer time (p < 0.05). Hardness, adhesiveness, springiness, cohesiveness, and resilience of fermented Som-fug decreased with a concomitant increase in weight loss, released water and expressible water contents when fish kept for a longer time were used (p < 0.05). L^∗, a^∗, b^∗, whiteness and the likeness for appearance, colour, texture and flavour of Som-fug decreased when fish kept in ice for an extended time were used (p < 0.05). However, the taste likeness was not affected by iced storage time (p > 0.05). No differences in overall liking were noticeable when fish kept in ice for up to 12 days were used for Som-fug production (p > 0.05). Therefore, the quality of fish used as raw material should be an important factor in determining the characteristics of Som-fug.     

Effect of electron beam irradiation on quality indicators of peanut butter over a storage period

Electron beam (e-beam) irradiation is an effective non-thermal processing step for the reduction of Salmonella in peanut butter. The objective of this study was to evaluate the effects of e-beam irradiation on quality indicators of peanut butter. Peanut butter samples were exposed to a range of e-beam doses and examined over a 14-day period at 22 °C. Colour analysis (L^∗, a^∗, b^∗), spreadability, peroxide values (PV) and thiobarbituric acid reactive substances test (TBARS) for lipid oxidation were monitored, fatty acid and amino acid profiles were verified and protein degradation was determined by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). Changes in colour, PV, and TBARS were observed as e-beam dose increased. No significant changes in spreadability were observed (P > 0.05). When applied to peanut butter, e-beam irradiation will produce significant changes in quality indicators; future studies should include sensory evaluation and consumer acceptance studies.     

Influences of potassium ferrocyanide on lipid oxidation of salted cod (Gadus morhua) during processing, storage and rehydration

The effects of added potassium ferrocyanide (CN) in different concentrations (2.5 ppm, 7.5 ppm and 100 ppm), in salt, on lipid oxidation in cod during salting, storage and rehydration were examined in this study. An increase in CN concentration accelerated lipid oxidation of the salted cod, as observed by increases in lipid hydroperoxides (PV) and thiobarbituric acid-reactive substances (TBARS), as well as in the development of fluorescence compounds (δF_or and δF_aq). A yellow discolouration (higher b^∗ value) of salted cod was associated with higher levels of oxidation derivatives. High correlation between PV, TBARS and free fatty acid (FFA), as well as between FFA and δF_or, was found. The results of principal component analysis showed that TBARS, b^∗ value and δF_or were the strongest indicators of lipid oxidation during salting and storage.     

Physicochemical changes of tilapia (Oreochromis niloticus) muscle during salting

The effect of wet and dry saltings on the physicochemical changes of tilapia (Oreochromis niloticus) muscle was investigated. Dry salting resulted in the higher rate of salt uptake into tilapia muscle facilitating the faster decrease in A_w (p < 0.05). The pH of both dry and wet salted fish muscles tended to decrease throughout the salting time and the lower pH was found in dry salted fish (p < 0.05). The increase in the protein content in the salting medium was found during wet salted tilapia production (p < 0.05). The TCA-soluble peptide content tended to decrease with increasing the salting time in both salting methods (p < 0.05), suggesting a leaching effect of the salting medium or the exudative loss occurred in salted tilapia. Wet salting caused the greater formation of metmyoglobin in tilapia muscle when compared to dry salting at all time points (p < 0.05) and the content of metmyoglobin increased as salting time increased in both salting methods (p < 0.05). A lowered metmyoglobin with a lowered redness index of dry salted tilapia muscle was found, indicating the continuous oxidation of metmyoglobin to other hypervalent derivatives and hence the discolouration of salted tilapia. Lipid hydrolysis and oxidation of tilapia meat occurred with varying degrees in both salting methods and these changes depended on salting time. Dry salting resulted in a higher oxidation of tilapia muscle lipid as indicated by the higher PV and TBARS throughout the salting period when compared with that of wet salting (p < 0.05). In conclusion, the physicochemical changes of tilapia muscle during salting are governed by the salting method and the salting time applied.     

Antioxidative activity of carnosine in gamma irradiated ground beef and beef patties

The activity of carnosine as a natural antioxidant in gamma irradiated ground beef and beef patties was studied. Samples of ground beef, in the absence and presence of 0.5% or 1.0% carnosine, as well as raw and cooked beef patties prepared with 1.5% salt (NaCl), in the absence and presence of 0.5% or 1.0% carnosine, were gamma irradiated at doses of 0, 2, and 4 kGy. The extent of oxidation in irradiated and non-irradiated samples of ground beef and raw beef patties was then determined during refrigerated (4 ± 1 °C) and frozen (−18 °C) storage, while determined for cooked beef patties during refrigerated storage only. Moreover, the determination of metmyoglobin (MetMb) accumulation and sensory evaluation for the visual color were carried out for samples of ground beef and raw patties. The results indicated that salt or salt and cooking accelerated the oxidative processes and significantly increased the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in the prepared non-irradiated samples. However, salt slowed down the accumulation of MetMb in raw patties. Irradiation treatments and storage in the absence of carnosine significantly (P < 0.05) increased the PV and TBARS in samples, at higher rates in salted or salted and cooked beef. Moreover, irradiation and storage significantly (P < 0.05) increased the formation of MetMb in ground beef and raw patties in the absence of carnosine. Addition of carnosine significantly (P < 0.05) reduced the oxidative processes and MetMb formation (proportionally to the used concentration) in samples post-irradiation and during storage. Furthermore, carnosine exerted significant efficacy in maintaining an acceptable visual red color post-irradiation and during storage of ground beef and raw patties. These results demonstrate that carnosine can be successfully used as a natural antioxidant to increase the oxidative stability in gamma irradiated raw and cooked meat products.     

Antioxidative properties of a chitosan–glucose Maillard reaction product and its effect on pork qualities during refrigerated storage

The objective of this study was to evaluate the antioxidative properties of a chitosan–glucose Maillard reaction product (CG-MRP), and its effect on pork qualities during refrigerated storage. Chitosan (1%), which was dissolved in acetic acid (1%) with 1.0%, 1.5%, or 2.0% glucose, pH adjusted to 6.0, autoclaved (121 °C, 15 min) and cooled, was prepared. The results showed that the 2,2-dipheny1-1-picrylhydrazy1 (DPPH) radical scavenging activities, ferrous ion chelating abilities, and reducing powers of various CG-MRP solutions were not significantly different. Pork loins soaked in the CG-MRP solutions or deionized water for 10 min and without dipping were stored at 4 °C for 7 days. Little influence was observed on the L∗, a∗, and b∗ colour values of the samples. Dipping in CG-MRP tended to retard the increases in volatile basic nitrogen (VBN) and thiobarbituric acid-reactive substances (TBARS) values, and resulted in lower microbial counts during storage. No detrimental influence on the sensory characteristics was found.     

Comparative studies on molecular changes and pro-oxidative activity of haemoglobin from different fish species as influenced by pH

Oxygenation, autoxidation as well as pro-oxidative activity of haemoglobins from tropical fish (Asian seabass, tilapia and grouper) as influenced by different pH (6, 6.5 and 7) were comparatively studied. Relative oxygenation of all haemoglobins decreased in the acidic conditions. Haemoglobin from Asian seabass was more oxygenated and stable against autoxidation at both pH 6 and 7, compared to those from tilapia and grouper. Haemoglobin from tilapia and grouper was fully oxidised at pH 6 after 120 h. Lipid oxidation of washed Asian seabass mince added with haemoglobin from various fish at different pH (6, 6.5 and 7) was monitored during 10 days of iced storage. Haemoglobins accelerated lipid oxidation more effectively at pH 6, compared with pH 6.5 and 7 as indicated by the higher peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS). At the same pH values, haemoglobins from tilapia and grouper were more pro-oxidative than that from Asian seabass as evidenced by the higher PV and TBARS (P < 0.05). Volatile lipid oxidation compounds detected by gas chromatography–mass spectrometry (GC–MS) were also formed at higher rate in the washed mince added with haemoglobin from tilapia or grouper with coincidental stronger fishy odour development, compared to the control and that added with haemoglobin from Asian seabass. Thus, lipid oxidation in fish muscle was more likely governed by haemoglobin, whose pro-oxidative activity varied depending upon the pH as well as molecular properties of haemoglobin.     

Effect of high pressure treatment on the quality of rainbow trout (Oncorhynchus mykiss) and mahi mahi (Coryphaena hippurus)

ABSTRACT:  High pressure processing (HPP) is becoming a promising seafood preservation method. The objective was to investigate the effect of HPP on quality of rainbow trout and mahi mahi during cold storage. Skinless fillets treated with different pressures (150, 300, 450, and 600 MPa for 15 min) and stored at 4 °C were analyzed at 1, 3, and 6 d storage. Red muscle was analyzed for lipid oxidation products by measuring thiobarbituric reactive substances (TBARS) and whole muscle was analyzed for total aerobic count, texture profile analysis, and color. A pressure of 300 MPa effectively inactivated the initial microbial population in rainbow trout (6-log reduction). However, inactivation of the initial population on mahi mahi was only about 4-log reduction at the same pressure. Microbial growth was significantly retarded after HPP. Color results showed that redness ( a * value) of rainbow trout at 300 MPa and above was significantly ( P < 0.05) lower compared to mahi mahi. TBARS values for rainbow trout increased with increased pressure, whereas the same trend was not seen for mahi mahi where maximum oxidation was found at 300 MPa and then declined. This study demonstrates the usefulness of HPP in seafood processing and the influence of species variation on processing parameters. The optimum HPP conditions for influencing lipid oxidation, microbial load, and color changes were found to be 300 MPa for rainbow trout and 450 MPa for mahi mahi.     

Comparison of spice-derived antioxidants and metal chelators on fresh beef color stability

Effects of Type I antioxidants eugenol and rosmarinic acid were compared to those of Type II antioxidants milk mineral (MM), sodium tripolyphosphpate (STPP), and phytate in raw ground beef held for 14 days at 4 °C in oxygen-permeable polyvinylchloride. Meat color stability was measured as % oxymyoglobin, Hunter a∗ value, chroma, and hue angle. Significant correlations (P < 0.0001) were observed between all color measurement methods. By day 14, STPP-treated patties lost more red color (P < 0.05 for a∗ and hue angle) and had higher thiobarbituric acid values than other treatments. By day 14, MM was as effective as eugenol and rosmarinate at preventing oxymyoglobin oxidation (72, 76, and 71% retained, respectively) and red color loss as measured by a∗ (9.2, 9.4, and 10.9), hue angle (58.4, 56.2, and 53.5), and chroma (17, 17, and 18), but was unable to inhibit microbial growth as effectively as the spice-derived antioxidants.     

Effect of sonication on colour,ascorbic acid and yeast inactivation in tomato juice

Power ultrasound is recognised as a potential non-thermal technique to inactivate micro-organisms pertinent to fruit juices. In this study tomato juice was sonicated at different amplitude levels (24.4–61.0 μm) at a constant frequency of 20 kHz for treatment times (2–10 min) and pulse durations of 5 s on and 5 s off. Hunter colour values (L∗, a∗ and b∗), pH, °Brix, titratable acidity, ascorbic acid and yeast inactivation were measured. No significant differences (p < 0.05) in pH, °Brix or titratable acidity were observed. Regression modelling was used to investigate the main effects of amplitude level and treatment time. Prediction models were found to be significant (p < 0.05) with low standard errors and high coefficients of determination (R²). Model predictions for critical quality parameters of Hunter colour values (L∗, a∗ and b∗), ascorbic acid and yeast inactivation were closely correlated with the experimental results obtained.     

Effect of pretreatment on lipid oxidation and fishy odour development in protein hydrolysates from the muscle of Indian mackerel

Impact of different pretreatments on chemical compositions of Indian mackerel mince was studied. Mince prepared using washing/membrane removal/alkaline solubilisation process (W–MR–Al) contained the lowest remaining myoglobin and haem iron content and also showed the lowest total lipid and phospholipid contents. When mince and W–MR–Al were hydrolysed using Alcalase for up to 120 min, a higher degree of hydrolysis (DH) was found in W–MR–Al after 30 min of hydrolysis. Furthermore, hydrolysate from W–MR–Al had lower peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and non-haem iron content throughout hydrolysis period (P < 0.05). When hydrolysate powder produced from mince and W–MR–Al (0–0.3% w/v) were fortified in milk, the former resulted in the lower likeness score (P < 0.05) at all levels used. The addition of the latter, for up to 0.2%, had no effect on likeness of all attributes, compared with milk without fortification (P > 0.05). Therefore, the appropriate pretreatment of mince yielded hydrolysate with lower fishy odour.