Physicochemical, microbiological, and sensorial characteristics of cooked, marinated, and vacuum-packed oysters under frozen storage

The phytochemical profile of moringa leaf and the combined effects of moringa leaf powder (MLP) with vacuum packaging on the biochemical, bacteriological and sensory attributes of Nile tilapia (Oreochromis niloticus) pickle during storage at room temperature (25 ± 5 ℃) for a period of 42 days were investigated. There were four treatments, such as control 1 (untreated; air pack), control 2 (untreated; vacuum pack), treatment 1 (1% MLP with vacuum packaging) and treatment 2 (2% MLP with vacuum packaging). The HPLC-ESI-Q-TOF-MS analysis showed the presence of several phenolic acids such as chlorogenic acids and quercetins in moringa leaf. During the storage period, MLP treated pickles exhibited significantly (P < 0.05) lower pH, total volatile basic nitrogen, free fatty acids, total viable count, and psychrotrophic bacterial count than the untreated pickles. Moreover, both MLP treated pickles had acceptable sensory characteristics up to 35 days of storage followed by control 2 (28 days) and control 1 (21 days) pickles. Findings of this research demonstrated that 1% MLP treated pickle with vacuum packaging delayed the quality deterioration and extended the shelf life for 14 and 7 days longer than control 1 and control 2, respectively during storage at room temperature. In conclusion, moringa leaf powder could be used as a natural additive of Nile tilapia pickles under vacuum packaging conditions to obtain better quality and storability during storage.

To determine the microbiological, biochemical and sensory changes of mussels during storage under aerobic, vacuum packaging (VP) and modified atmosphere packaging (MAP) conditions at 4 degrees C, and to determine shelf-life of mussels under the same packaging conditions using the above assessment parameters. Aqua-cultured mussels (Mytilus galloprovincialis) were obtained from a local culture farm, packaged aerobically under VP and MAP (50%/50% CO2/N2: M1, 80%/20% CO2/N2: M2, 40%/30%/30% CO2/N2/O2: M3), and stored at 4 degrees C. Quality evaluation was carried out using microbiological, chemical and sensory analyses. Microbiological results revealed that the M2 and VP delayed microbial growth compared with that of air-packaged samples. The effect was more pronounced for total viable count (TVC), Pseudomonas spp., lactic acid bacteria (LAB) and H2S-producing bacteria. TVC was reduced by 0.9-1.0, Pseudomonas spp. by 0.7-0.8, LAB by 1.0-2.2, H2S-producing bacteria by 0.7-1.2. Enterobacteriaceae were not significantly affected by MAP conditions. Of the chemical indices determined, the total volatile basic nitrogen and trimethylamine nitrogen values remained lower than the proposed acceptability limits of 35 mg N 100 g(-1) and 12 mg N 100 g(-1), respectively, after 15 days of storage. Both the VP and air-packaged mussel samples exceeded these limits. The thiobarbituric acid value of all MAP and VP mussels remained lower than the proposed acceptability limit of 1 mg malondialdehyde kg(-1). The air-packaged samples exceeded this limit. All samples retained desirable sensory characteristics during the first 8 days of storage. Based on odour and taste evaluation, the M1 and M3 samples remained acceptable until ca day 11-12, the M2 samples remained acceptable until ca day 14-15 days while the VP and air-packaged mussel samples remained acceptable until ca days 10-11 and 8-9 of storage respectively. Based primarily on sensory, but also on biochemical and microbiological parameters determined, M2 gas mixture was the most effective for mussel preservation achieving a shelf-life of ca 14-15 days. MAP (M2) can be used to increase the shelf-life of refrigerated mussels. A shelf-life extension of refrigerated mussels by ca 5-6 days under MAP may be obtained.

The aim of the study was to evaluate quality of ready-to-cook (RTC) hilsa curry under not sealed pack as control, vacuum as T1, MAP-1 (50% CO2 & 50% N2) as T2, and MAP-2 (40% CO2 , 30 N2 & 30% O2) pack as T3 during storage at 4±1°C. For this purpose, pH, total volatile base nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS) and aerobic plate count (APC) of three samples from each treatment were analyzed at four days interval during 28 days of storage. The pH and TVB-N values of RTC hilsa curry were within the standard limit in all samples during the storage period. However, significantly (p <0.05) lower values were observed on and after the 12th day for pH and 16th day for TVBN in all samples compared to the control. TBARS gradually increased from the 4th day for all samples except vacuum packaged sample. However, significantly (p <0.05) lower TBARS were observed in the vacuum and MAP-1 samples on and after the 8th day of storage compared to the control and MAP-2 samples. APCs gradually increased from the initial value of 5.25 log CFU/g with time in all samples. However, significantly (p <0.05) lower APCs were observed on and after the 16th day of storage in all samples compared to the control sample. The APCs exceeded the 7 log CFU/g, which is considered as the upper acceptable limit on approximately 16th day for the control, 24th day for vacuum, 22nd day for MAP-1, and 20th day for MAP-2 sample. Therefore, the vacuum packaging demonstrated the better results, which the superstores can utilize conveniently to display RTC hilsa curry with prolonged shelf life. J. Bio-Sci. 29(2): 71-79, 2021 (December)

Shelf-life of chilled fresh Mediterranean swordfish ( Xiphias gladius) stored under various packaging conditions: : Microbiological, biochemical and sensory attributes

Effects of vacuum packaging (VP) and lactoperoxidase system–whey protein coating (LPOS + WPS) combination on maintaining quality of Pike–Perch fillets during 16 days of cold storage (4 ℃) were studied. Quality assessment was based on microbial (total viable counts, psychrotrophic bacteria, and H2S producing bacteria), chemical (TVBN, TBARS, and pH), and sensory (odor, color, texture, and overall acceptability) analysis. Results of microbial analysis showed significantly (P < 0.05) lower bacterial load in WPS + LPOS + VP than other groups, while highest bacterial load observed in WPS. Similarly, bacterial count, and lowest and highest amount of total volatile basic nitrogen (TVBN) observed in WPS + LPOS + VP and WPS, respectively. Thiobarbituric acid reactive substances (TBARS) values assessment showed that lipid oxidation in WPS + LPOS + VP was significantly (P < 0.05) lower than other groups, while in WPS was highest. Combined VP and WPS + LPOS could maintain the stability of initial pH during cold storage. Sensory results indicated that the shelf-life of Pike–Perch fillets in WPS, WPS + LPOS, WPS + VP, and WPS + LPOS + VP were at least 4, 8, 4, and 16 days, respectively. The results suggested that combined VP and LPOS + WPS can be recommended to extend shelf-life of fish in cold storage. This strategy would be beneficial to the fishery industry as well as the retail market and consumer.

The effect of modified atmosphere packaging (MAP 1: 70% CO2/30% N2 and MAP 2: 50% CO2/30% N2/20% O2) and vacuum packaging (VP), on the shelf-life of chub mackerel (Scomber japonicus) fillets stored under refrigeration was studied. Quality assessment was based on sensory analysis and biochemical indices determination. Increase in total volatile basic nitrogen (TVBN) and trimethylamine nitrogen (TMAN) followed the order: MAP 1 < MAP 2 < VP < air (control samples). The presence of oxygen into the fish package (air or MAP) resulted in an increase in the 2-thiobarbituric acid (TBA) values in comparison with samples packaged in the absence of oxygen. The most effective MAP used was MAP 1 which contributed to a considerably slower rate of fish spoilage. Based primarily on odour scores it was observed that raw chub mackerel fillets stored in the presence of air remained acceptable up to ca. 11 days, VP and MAP 2 samples up to ca. 15–16 days, while MAP 1 samples up to ca. 20–21 days of storage. On the other hand, flesh texture and flesh colour of all packaged samples received scores above or equal than the acceptability limit up to ca. 13–14 days of storage.

In this study, the antioxidant, antimicrobial and sensory effects of honey propolis extract as a natural preservative in beef burgers were investigated. First, propolis extract was produced at different percentages (0.5, 1.0, and 2.0%), and the control treatment, containing 0% propolis extract, was produced with a beef burger. The pH, antioxidant 2,2-diphenyl-1-picrylhydrazyl (DPPH), thiobarbituric acid (TBA), total volatile base nitrogen (TVB-N), and microbial characteristics (total microbial count, Escherichia coli, Staphylococcus aureus, mold, and yeast) and sensory characteristics (color, smell, texture and overall acceptance) during the storage period were subsequently investigated over a period of 8 days (0, 4, and 8). The results of the evaluation of different properties revealed that adding propolis extract to hamburger samples caused a significant decrease in pH, TBA, TVN, and microbial properties (total microbial count, E. coli, S. aureus, mold, and yeast) (p &lt; 0.05). On the other hand, the amount of antioxidant property and sensory evaluation (color, smell, texture, and overall acceptance) also increased with the addition of propolis extract (p &lt; 0.05). Additionally, the duration of storage caused a significant increase in pH, TBA, TVN, and microbial characteristics (total microbial count, E. coli, S. aureus, and mold and yeast), and a reduction in antioxidant properties and sensory evaluation (color, smell, texture, and overall acceptability) were found in hamburger samples (p &lt; 0.05). The use of 2% propolis extract improved the oxidation properties and maintained the sensory properties during 8 days of storage for hamburger. Therefore, the use of 2% propolis extract improves the antioxidant and antimicrobial properties of hamburgers during storage and is a superior treatment.

The effects of air-packed (AP) and vacuum-packed (VP) on quality and microbial characteristics of silver carp (Hypophthalmichthys molitrix) fillets during chilled storage (4 ± 1 °C) were investigated. The fillets were analyzed for sensory scores, total volatile basic nitrogen (TVB-N), ATP-related compounds (ATP, IMP, HxR, and Hx), K value, and biogenic amines (BAs). The results proved that VP inhibited the increase of microorganisms, TVB-N, Hx, and putrescine in silver carp, and slowed the reduction in sensory score. Therefore, VP can be applied for preservation of the silver carp fillets to improve its quality. For identification, 16S rRNA genes of the isolated pure strains were sequenced and analyzed. On the initial day of storage, Chryseobacterium was the dominant bacterial genus. At the end of shelf life, Pseudomonas was the most common group in AP fillets and Aeromonas followed by Yersinia were found mainly in VP samples. Practical applications Silver carp (Hypophthalmichthys molitrix) are distributed widely in fresh water systems. The world aquaculture production of silver carp was 4,354,638 tons, and it ranked second highest among freshwater fish species in 2015, but they are perishable during storage because of microbial spoilage and biochemical reactions. Vacuum packaging (VP) has proved to be effective for extending the shelf-life of aquatic products by excluding oxygen that prevents the growth of spoilage bacterial. However, little information is available on the microbial succession of VP silver carp. Therefore, this work was to determine the differences of microbiological succession on chilled silver carp fillets under air-packed (AP) and VP conditions using a combination of culture-based and 16S rRNA gene analysis methods. Furthermore, this study will give valuable information about development and spoilage of VP silver carp fillets.

This study was carried out to evaluate the impact of gamma irradiation and turmeric powder (TP) on microbial quality (total aerobic bacteria and coliforms), physicochemical quality (pH, Hunter’s parameter, oxidative and microbial stabilities, haem pigment), stability, and antioxidant status of chicken meat. Accordingly, two doses (1 kGy and 2 kGy) of gamma irradiation alone and in combination with 3% TP along with the control (0 kGy) were applied. Aerobic and vacuum packaging were used for storage of chicken meat on the 0, 7th, and 14th days of storage at refrigeration temperature (4°C). The microbiological results showed that the contamination level decreased as the dose of gamma irradiation was increased for both total bacteria and coliforms, whereas no contamination was documented in the group treated with 2 kGy+TP for both aerobic and vacuum packaging. The results further showed that pH, haem pigment, and Hunter’s colour were also significantly influenced with respect to different groups. The peroxide value (POV), thio-barbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVBN) differed significantly in chicken meat with different treatments and storage intervals. Higher POV and TBARS were noticed in chicken meat treated with 2 kGy under aerobic packaging after 14 days of storage, and TVBN was higher in the control on the 14th day under aerobic packaging. Total phenolics and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity were also higher in chicken meat treated with 2 kGy + TP on 0 day of storage. Furthermore, higher sensory attribute scores for attributes like appearance, taste, texture, flavour, and overall acceptability were found in the 2 kGy-treated group. It is concluded that chicken meat treated with 2 kGy+TP was considered better for microbial and physicochemical quality, antioxidant activity as well as sensorial properties of chicken meat.

ABSTRACTSeabream farmed fillets were packaged under aerobic, vacuum, and modified atmosphere (40% CO2, 30% N2, 30% O2) conditions, and they were stored at 3 ± 1ºC for 14 days, under retail conditions. Microbiological (total viable counts, psychrotrophic bacteria, coliform/E. coli, Enterobacteriaceae, lactic acid bacteria, Pseudomonas, and anaerobic bacteria), physical-chemical (color, pH, water holding capacity, thiobarbituric acid, total volatile basic nitrogen, and trimethylamine), and sensory descriptive analysis were carried out at 0, 4, 7, 11, and 14 days of storage. There was a significant effect of storage time for all three packaging types. Significantly lower levels of total volatile basic nitrogen and trimethylamine were observed in modified atmosphere packaged and vacuum packaged seabream fillets during storage time. Vacuum packaged fillets showed higher oxidative stability. In general, both packaging conditions—vacuum and modified atmosphere—improved microbiological and sensorial quality of the fish fillets. Results showed that modified atmosphere packaging (40% CO2, 30% N2, 30% O2) and especially vacuum packaging are good alternatives to extend the shelf life of seabream refrigerated fillets.

This study is focused on the effect of phycobiliprotein extraction of Gracilaria on the quality of common carp burgers, and the application of nanoliposomes containing pigment in the improvement of its antimicrobial and antioxidant activity of burgers during refrigerated storage in 18 days. Burgers were incorporated with phycobiliprotein and liposomal phycobiliprotein (2.5% and 5% w/w), and their chemical and microbial changes in terms of pH, peroxide value (PV), thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), total viable counts (TVC), psychrotrophic bacterial counts (PTC), and sensory characteristics were evaluated. Results presented a nanoliposome size of about 515.5 nm with capable encapsulation efficiency (83.98%). Our results showed non-encapsulated phycobiliprotein could delay the deterioration of common carp burgers, as a reduction in PV, TBA, and TVB-N, TVC, and PTC values in burgers treated with free and nano encapsulated phycobiliprotein. Moreover, the potential of phycobiliprotein was improved when it was encapsulated into chitosan coated liposomes. Burgers treated with 5% nanoliposomes displayed the lowest amount of lipid oxidation and microbial deterioration in comparison to others during storage. According to chemical, microbial and sensory evaluation, the shelf life of common carp burgers was increased in samples treated with encapsulated phycobiliprotein at 2.5% and 5%, as compared to the control (p ≤ 0.05).

The aim of our research was to examine the influence of packaging in modified atmosphere and vacuum on the total volatile basic nitrogen (TVB-N) content in muscle of rainbow trout (Oncorhynchus mykiss) and common carp (Cyprinus carpio), as well as to determine the most suitable gas mixtures for packing of these freshwater species. Three sample groups of trout and carp cuts were investigated. The two groups were packaged in modified atmosphere with different gas ratios: 90%CO2+10%N2 (MAP 1) and 60%CO2+40%N2 (MAP 2), whereas the third group of fish cuts were vacuum packaged. During trials, the trout and carp cuts were stored in refrigerator at 3°C±0.5°C. Determination of TVB-N was performed on 1, 4, 7, 9, 12 and 14 days of storage. The obtained results indicate that the investigated mixtures of gases and vacuum had a significant influence on the values of TVB-N in trout and carp cuts. The lowest increase in TVB-N was established in trout and carp cuts packaged in MAP 1, whereas the highest increase was established in vacuum packaged cuts. Based on the obtained results, it can be concluded that the gas mixture consisting of 90% CO2 and 10% N2 was the most suitable for packaging of fresh trout and carp cuts in terms of TVB-N value.

Characterization of the microbial composition and quality of lightly salted grass carp (Ctenopharyngodon idellus) fillets with vacuum or modified atmosphere packaging

Vacuum and modified atmosphere packaging are widely used for preserving food items including fish. In this context, the quality and shelf life of air- (control), vacuum- and nitrogen-packed dried barb fish (Puntius spp.) stored at ambient temperature were evaluated through biochemical and microbial analyses for 90 days. In most of the storage days, significantly lower values of moisture, total volatile base-nitrogen (TVB-N) and peroxide value (PV) were observed in the vacuum pack sample compared to control. However, the TVB-N, PV, total coliforms and faecal coliforms counts were within the acceptable limit in all groups. The total plate count (TPC) increased gradually with time from an initial value of 4.29 log CFUg–1. However, compared to control, significantly lower TPC were found on and after the 30th day of storage in vacuum and nitrogen pack samples. Considering the TPC value of 5 log CFUg–1, the shelf life was determined at approximately 15 days for control, 35 days for nitrogen pack and 45 days for vacuum pack samples. Therefore, the vacuum pack is considered the best packaging, which may be utilised by the processors to produce and retail the dried products with prolonged shelf life.

The aim of the present study was to investigate the combined effect of chitosan dip (1% w/v) and vacuum packaging on the shelf life of fresh chicken burgers packaged in LDPE/PA/LDPE bags and stored at 4 ± 1°C for up to 12days. Furthermore, the possible correlation among microbiological, physico-chemical and sensory indices was investigated. Burger treatments included: aerobic packaging (AP, control), vacuum packaging (VP), chitosan dipping (CHI), and vacuum packaging plus chitosan dipping (VP + CHI). Microbiological [Total viable count (TVC), Pseudomonas spp., Brochothrix thermosphacta, Enterobacteriaceae, Lactic acid bacteria (LAB)], physicochemical [color, pH, total volatile basic Nitrogen (TVB-N), and Thiobarbituric acid (TBA)] and sensory (odor, taste, and texture) analyses were carried out. Results showed that the majority of microbiological, physico-chemical, and sensory analysis parameters varied significantly (p < 0.05) depending on treatment. Based primarily on sensory, followed by microbiological and physico-chemical data, the shelf life of chicken burgers was 4days for AP samples, 8days for VP samples, 10days for CHI treated samples, and 12days for the VP + CHI treated samples. Finally, a positive and significant correlation (p < 0.05) was observed among most microbiological, sensory, and physico-chemical data, introducing new data relating initial TVC to TVB-N values regarding alternative treatments of minced chicken meat for its optimum preservation.