The content of indole and the pH have been determined post mortem in shrimps (Pandalus borealis) caught in the Barents Sea and in shrimps caught outside Malaysia, India and Taiwan. These two criteria were compared with organoleptic assessment and the contents of volatile nitrogen bases (ammonia, trimethylamine) and living bacteria. For shrimps caught in the Barents Sea, both raw shrimps stored in ice and processed (broiled, peeled and single-frozen) shrimps were investigated. The results showed that only low levels of indole had been formed during ice-storage. Not until an advanced state of spoilage could a distinct increase in the indole content in raw and in boiled, peeled shrimps be discerned. pH increased slowly and varied in the area between acceptable and not acceptable quality. Neither the indole content nor the pH seems therefore to be a useful criterion for quality assessment either of raw shrimps caught in the Barents Sea or of such shrimps after processing (boiling and peeling). Most of the samples of boiled, peeled shrimps from the Far East were assessed organoleptically as less good-spoiled, and bacterial growth was significant. The content of trimethylamine oxide and volatile nitrogen was low, while the content of indole was high and exceeded 25 microgram/100 g in 8 or 14 samples. This is the upper limit for import in USA. The content of indole seems to be an important quality criterion for shrimps caught in warmer countries. The content of indole exceeded 25 microgram/100 g in some samples which were assessed organoleptically as acceptable. The pH was lower in brine-treated shrimps than in the others.
The oxidative stability of sunflower oil supplemented with medicinal split gill mushroom, Schizophyllum commune's crude extract (CE), the formic acid (FA) fraction and semipurified subfractions (SF) II and IV were tested, compared to BHA and alpha-tocopherol, by measuring their peroxide value, iodine value, p-anisidine value, thiobarbituric acid-reactive substances, and free fatty acid content. Their total phenolic content (TPC), 2,2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging, and ferric reducing/antioxidant power (FRAP) were also evaluated. FA and CE exhibited highest DPPH* scavenging, while FA and SFIV showed the highest FRAP; TPC was found to be highest in CE, FA, and SFIV. BHA and alpha-tocopherol are more protective in stabilizing the sunflower oil; SFII and SFIV had short-term protective effect in secondary oxidation for 1 year, while CE and FA retarded secondary oxidation and extended the shelf life 1 1/2 years and 2 years, respectively. HPLC-DAD analysis found (+)-catechin in Sch. commune's extracts. Sch. commune's extracts did not show similar retardation of lipid oxidation in sunflower oil as compared to alpha-tocopherol and BHA at the 200 ppm level. However, the higher concentration of Sch. commune's extract that provided the protective effect in stabilizing sunflower oil can be further studied.
The study compares the bacteriological quality on Asian seabass (Lates calcarifer) between ice and salt storage methods. The main objectives of the study were to identify different bacteria constituents and quantitative bacterial load in Asian seabass when preserved with ice and sea salt. For the purpose of this study, Asian seabass was stored in two different conditions of ice-chilled and salted for 2 days. All fish samples were analyzed by performing bacteriological analysis and the isolated bacteria were identified by using API identification system. In case of the quantity of bacteria in the flesh, Chilling and salting had no significant difference to the quantity of bacteria on fish flesh. As for the skin, salt-preserved fish showed higher quantity of bacteria than ice-preserved fish. Acinetobacter baumannii and Pseudomonas fluorescens had been identified from skin sample of ice-chilled fish. Besides P. fluorescens and A. baumannii other isolates identified include Vibrio and Myxobacteria. All bacteria were cocci-shaped except a few bacilli. In term of bacteria number and morphological characteristics, ice-chilled preserved fish was better than salt preserved fish. Overall, less number of bacteria was observed in both ice-chilled and sea salt preserved fish. The result of this study indicated that the quick preservation is a very important factor to control bacterial load in the preserved fish.
Chicken breast muscle powder (CBMP) and modified waxy cornstarch (MWCS) blends were prepared at different pH conditions (pH 4, 5, 6, 7, 8, and 9). The blends were characterized by light microscopy, frequency sweep, flow analysis, and freeze-thaw stability analysis. Light microscopy showed that the blend structure was coarse at pH conditions close to the isoelectric point of protein and became finer with increasing pH. Frequency sweep demonstrated that the blend was more liquid-like with relatively lower storage (G') and loss (G'') moduli as the pH was increased from pH 4 to pH 9. Flow analysis revealed that thixotropy behavior was evident in samples treated at pHs 4 and 5, whereas antithixotropy was shown by those adjusted to pHs 6, 7, 8, and 9. The CBMP-MWCS blends were found to show better freeze-thaw stability at pH 8 that could be attributed to the formation of a highly interactive network structure of CBMP and MWCS.
The composite effects of gum arabic (GA) (5, 10, 15, and 20%) and chitosan (CH) (1.0%) on the biochemical and physiological characteristics of banana fruits stored at 13 ± 1 °C and 80 ± 3% relative humidity (RH) for 28 days and afterward for 5 days at simulated marketing conditions (25 °C, 60% RH) were investigated. Significant (P ≤ 0.05) differences were observed for the entire GA plus CH treatments as compared to the control. However, the results showed that after 33 days of storage, the weight loss and soluble solids concentration of fruits treated with 10% GA plus 1.0% CH composite coating were 24 and 54% lower, whereas fruit firmness, total carbohydrates, and reducing sugars were 31, 59, and 40% higher than the control, respectively. Furthermore, the composite edible coating of 10% GA plus 1.0% CH delayed color development and reduced the rate of respiration and ethylene evolution during storage as compared to the control. Similarly, sensory evaluation results also proved the effectiveness of 10% GA plus 1.0% CH composite coating by maintaining the overall quality of banana fruits. Consequently, the results of scanning electron microscopy also confirmed that the fruits coated with 10% GA plus 1.0% CH composite edible coating had very fewer cracks and showed a smooth surface. These findings suggest that 10% GA plus 1.0% CH as an edible composite coating can be used commercially for extending the storage life of banana fruits for up to 33 days.
The practicality of biometrics of seafood cannot be overemphasized, particularly for competent authorities of the shrimp industry. However, there is a paucity of relevant literature on the relationship between biometric and physicochemical indices of freshly harvested shrimp. This work therefore investigated the relationship between biometric (standard length (SL), total weight (TW) and condition factor (CF)) and physicochemical (moisture content, pH, titratable acidity, water activity, water retention index, colour values and fracturability) characteristics of freshly harvested Pacific white shrimp (Litopenaeus vannamei) obtained from three different farms. The relationships between these parameters were determined using correlation and regression analyses.
The objective of this study was to compare the physico-chemical characteristics and antioxidant activity of ozone-treated papaya fruit and untreated fruit. Freshly harvested papaya fruit were exposed continuously to ozone fumigation (0, 1.5, 2.5, 3.5 and 5ppm) for 96h prior to ambient storage at 25±3°C and 70±5% relative humidity (RH) for up to 14days. The fruit exposed to 2.5ppm ozone had higher levels of total soluble solids (25.0%), ascorbic acid content (12.4%), β-carotene content (19.6%), lycopene content (52.1%), and antioxidant activity (30.9%), and also reduced weight loss (11.5%) at day 10 compared to the control. The sensory attributes of papaya treated with 2.5ppm ozone was superior in sweetness and overall acceptability. These results support the application of ozone as a non-thermal and safe food preservation technique for papaya which can benefit both the producers and consumers.
Microbial contamination annually leads to substantial food resource loss. Effective food packaging can mitigate food contamination and waste, yet conventional materials such as plastics often lack bacteriostatic activity. This study aimed to synthesise FengycinA-M3@bacterial cellulose@polyvinyl alcohol composite hydrogels via dual cross-linking with hydrogen and borate bonding, with the goal of enhancing antibacterial properties and prolonging the preservation period of refrigerated chicken breast. The composite hydrogel was subjected to comprehensive characterisation for structural, mechanical, water absorption, slow peptide release, antimicrobial capacity, biocompatibility, and chicken breast freshness preservation. The results showed that the composite hydrogel had a porous network structure and excellent gel elasticity and biocompatibility. It was effective in inhibiting Staphylococcus aureus and Escherichia coli, and prolonged the storage time of frozen chicken breast for up to 12 days. These findings emphasise the potential of hydrogel food packaging to prolong storage periods and its suitability for food industry applications due to ease of manufacture.
The emergence of bacterial resistance against conventional antibiotics and the growing interest in developing alternative, natural antibacterial agents have prompted the search for plant-derived antibacterial peptides in recent decades. Different classes of endogenous antibacterial peptides have been identified from various plant species. Moreover, protein hydrolysates and hydrolysate-derived peptides with potent antibacterial effects have also been identified from numerous plant sources. Antibacterial peptides are often cationic and amphipathic, consisting of fewer than 100 amino acids. They are able to disrupt bacterial membrane integrity via pore formation and/or compromise bacterial metabolic processes. In this review, we summarize current knowledge on the characteristics and modes of action of antibacterial peptides, as well as salient points concerning the production of antibacterial protein hydrolysates from plant proteins. Examples of plant-derived antibacterial hydrolysates and peptides will be highlighted, with particular attention to less explored seeds, fermented plant foods and agricultural by-products. Promising future research directions with regards to the application of plant-derived antibacterial hydrolysates and peptides in food preservation, farm animal disease management, and nutraceutical/functional food development will be proposed.
In the present study, gelatin-carboxymethyl cellulose blend film was synthesized, characterized and applied for the first time to preserve cherry tomatoes (Solanum lycopersicum var. cerasiforme) and grapes (Vitis vinifera). Gelatin (Gel) film forming solution was incorporated with carboxymethyl cellulose (CMC) at three volume per volume (Gel:CMC) ratios, namely 75:25, 50:50 and 25:75. CMC treatment has improved the transparency, tensile strength (TS), elongation at break (EAB), water vapor permeability and oxygen permeability of gelatin films. A pronounced effect was obtained for 25Gel:75CMC film. The TS and EAB values were increased from 25.98 MPa and 2.34% (100Gel:0CMC) to 37.54 MPa and 4.41% (25Gel:75CMC), respectively. A significant improvement in antimicrobial property of gelatin films against two food pathogens, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was obtained in the presence of CMC. The effectiveness of gelatin-CMC blend films to extend the shelf life of agricultural products was evaluated in a 14-day preservation study. The gelatin-CMC films were successfully controlled the weight loss and browning index of the fruits up to 50.41% and 31.34%, respectively. Overall, gelatin-CMC film is an environmental friendly film for food preservation.
Chemical preservatives have been used in the food industry for many years. However, with increased health concerns, consumers prefer additive-free products or food preservatives based on natural products. This study evaluated antimicrobial activities of extracts from Emilia sonchifolia L. (Common name: lilac tassel flower), Tridax procumbens L. (Common name: tridax daisy) and Vernonia cinerea L. (Common name: Sahadevi), belonging to the Asteracea family, to explore their potential for use against general food spoilage and human pathogens so that new food preservatives may be developed. Three methanol extracts of these plants were tested in vitro against 20 bacterial species, 3 yeast species, and 12 filamentous fungi by the agar diffusion and broth dilution methods. The V. cinerea extract was found to be most effective against all of the tested organisms and the methanol fraction showed the most significant (p < 0.05) antimicrobial
activity among all the soluble fractions tested. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 1.56 to 100.00mg/mL. The MIC of methanol fraction was the lowest in comparison to the other four extracts. The study findings indicate that bioactive natural products from these plants may be isolated for further testing as leads in the development of new pharmaceuticals in food preservation as well as natural plant-based medicine.
Bacterial spores have special significance in foods because they are much more resistant to physical and chemical antimicrobial treatment. Nowadays, there is interest in using natural products such as plant extract for food preservation. In this study, 26 of tropical medicinal plants and spices were screened for their sporicidal activity against the spores of Bacillus cereus. The spores of B. cereus was harvested after incubation at 30°C for 1 week and treated with various plant extracts using the method of Standard Operating Procedure for the AOAC (Association of Official Analytical Chemists) Sporicidal Activity. Glutaraldehyde was used as a positive control. Among them, Indonesian bay leaf (Eugenia polyantha Wight) inactivated more than 3 log of spores/ml of B. cereus (99.99%) at the concentration of 1% and completely killed B. cereus spores at concentration of 2.5%. These results suggest that Indonesian bay leaf extract has strong sporicidal activity against spores of B. cereus.
The characterization and fat migration of palm kernel stearin (PKS) and desiccated coconut, used as base filling centre in dark chocolate were studied. C36 and C38 triglycerides of PKS decreased by 11% and 9.6% respectively, whereas C32 and C34 increased by 97% and 48% respectively. The change in the triglycerides composition of PKS shift the melting point of PKS from 33.2 to 31.4 degrees C. Solid fat content (SFC) of PK reduced by 40% at 30 degrees C. The rate of fat migration was very slow at 18 degrees C storage compared to 30 degrees C. The rate of change of C36 in the chocolate layer was 0.1% week-1 and 1.2% week-1 at 18 and 30 degrees C respectively. Chocolate stored at 18 degrees C showed post hardening during storage period and withstood bloom during the storage period, whereas that stored at 30 degrees C became soft and bloomed faster after 3 weeks of storage.
Four formulations were processed into frankfurters with different ratios of mechanically deboned chicken meat (MDCM) and cooked chicken skin (CCS) i.e. 80/0, 70/10, 60/20 and 50/30. The products were evaluated for proximate composition, cholesterol content, colour; 'L' value (lightness) and 'a' value (redness), percentage of cooking loss, physical measurements (shearforce-kgf and folding test), thiobarbituric acid value (TBA) and taste panel evaluation. The increment of CCS in the frankfurters increased the contents of moisture, ash, protein, fat, cholesterol, the lightness ('L' value) and redness ('a' value). After 3 months of frozen storage, the increment continued except for the moisture contents for formulations with 20 and 30% CCS. The lipid oxidation (TBA value) and cooking loss were lowered in formulations with CCS. After 3 months of frozen storage, TBA value decreased, while the cooking loss increased for all the formulations. The addition of CCS increased hardness of the frankfurters but affected folding ability, with formulation with 10% CCS scoring better grade. Sensory evaluation was carried out using 30 untrained panelists to evaluate aroma, colour, appearance, hardness, juiciness, chicken taste, oily taste, rancid taste and overall acceptance of the products. The addition of CCS in the frankfurters at 10 and 20% resulted in products with taste and texture that were acceptable after 3 months of frozen storage.
BACKGROUND: The marketability of fresh-cut banana slices is limited by the rapid rate of fruit softening and browning. However, there is no scientific literature available about the role of postharvest calcium propionate and chitosan treatment on the quality attributes of fresh-cut banana. Therefore, the aim of the present study was to investigate these effects.
RESULTS: The application of calcium propionate plus chitosan (CaP+Chit) retained higher firmness, higher ascorbic acid content, higher total antioxidant activity and higher total phenolic compounds, along with lower browning, lower polyphenol oxidase, lower peroxidase, lower polygalacturonase and lower pectin methyl esterase activities and microbial growth, compared to control banana slices after 5 days of cold storage.
Oxalic acid was evaluated as a treatment for reducing populations of naturally occurring microorganisms on raw chicken. Raw chicken breasts were dipped in solutions of oxalic acid (0, 0.5, 1.0, 1.5, and 2.0%, wt/vol) for 10, 20, and 30 min, individually packed in oxygen-permeable polyethylene bags, and stored at 4 degrees C. Total plate counts of aerobic bacteria and populations of Pseudomonas spp. and Enterobacteriaceae on breasts were determined before treatment and after storage for 1, 3, 7, 10, and 14 days. The pH and Hunter L, a, and b values of the breast surface were measured. Total plate counts were ca. 1.5 and 4.0 log CFU/g higher on untreated chicken breasts after storage for 7 and 14 days, respectively, than on breasts treated with 0.5% oxalic acid, regardless of dip time. Differences in counts on chicken breasts treated with water and 1.0 to 2.0% of oxalic acid were greater. Populations of Pseudomonas spp. on chicken breasts treated with 0.5 to 2.0% oxalic acid and stored at 4 degrees C for 1 day were less than 2 log CFU/g (detection limit), compared with 5.14 log CFU/g on untreated breasts. Pseudomonas grew on chicken breasts treated with 0.5% oxalic acid to reach counts not exceeding 3.88 log CFU/g after storage for 14 days. Counts on untreated chicken exceeded 8.83 log CFU/g at 14 days. Treatment with oxalic acid caused similar reductions in Enterobacteriaceae counts. Kocuria rhizophila was the predominant bacterium isolated from treated chicken. Other common bacteria included Escherichia coli and Empedobacter brevis. Treatment with oxalic acid caused a slight darkening in color (decreased Hunter L value), retention of redness (increased Hunter a value), and increase in yellowness (increased Hunter b value). Oxalic acid has potential for use as a sanitizer to reduce populations of spoilage microorganisms naturally occurring on raw chicken, thereby extending chicken shelf life.
In the search for new preservatives from natural resources to replace or to reduce the use of chemical preservatives 4 strains of lactic acid bacteria (LAB) were selected to be evaluated for their antifungal activity on selected foods. The supernatants of the selected strains delayed the growth of fungi for 23 to 40 d at 4 °C and 5 to 6 d at 20 and 30 °C in tomato puree, 19 to 29 d at 4 °C and 6 to 12 d at 20 and 30 °C in processed cheese, and 27 to 30 d at 4 °C and 12 to 24 d at 20 and 30 °C in commercial bread. The shelf life of bread with added LAB cells or their supernatants were longer than normal bread. This study demonstrates that Lactobacillus fermentum Te007, Pediococcus pentosaceus Te010, L. pentosus G004, and L. paracasi D5 either the cells or their supernatants could be used as biopreservative in bakery products and other processed foods.
Research was conducted to manufacture and evaluate a restructured turkey breast product using the Fibrimex cold-set binding system, sodium diacetate (NaD), and sodium lactate (NaL) and to ascertain effects of the treatments on proximate composition, pH, psychrotrophic organisms, water activity, onset of rancidity (TBA), thaw loss, cooking yields, and objective color, and sensory characteristics. Whole turkey breasts were cut into 5-cm-thick strips; treated with either water only (control), 1.5% NaL, 2.0% NaL, 0.1% NaD, 1.5% NaL + 0.1% NaD, or 2.0% NaL + 0.1% NaD; blended with Fibrimex ingredients; stuffed into casings; and stored at -30 degrees C for 0, 1, 2, and 3 mo. After each storage period, frozen chubs were tempered at 4 degrees C, sliced into 1-cm-thick steaks, packaged in retail trays, stored at 0 degrees C to simulate retail storage, and analyzed after 0, 2, 4, 6, 8, and 10 d. Sodium diacetate used alone or in combination with NaL reduced (P < 0.05) growth of psychrotrophic organisms and had no adverse effects on water activity, pH, cooking yield, fat, moisture, protein, objective color, onset of rancidity, and sensory characteristics (juiciness, turkey flavor intensity, and tenderness). Panelists reported slight off-flavor in all steaks treated with NaL. Treating steaks with NaL alone or in combination with NaD resulted in increased (P < 0.05) ash content. Sodium lactate also functioned to minimize thaw loss in the frozen restructured turkey product.
Edible seaweeds are a good source of antioxidants, dietary fibers, essential amino acids, vitamins, phytochemicals, polyunsaturated fatty acids, and minerals. Many studies have evaluated the gelling, thickening and therapeutic properties of seaweeds when they are used individually. This review gives an overview on the nutritional, textural, sensorial, and health-related properties of food products enriched with seaweeds and seaweed extracts. The effect of seaweed incorporation on properties of meat, fish, bakery, and other food products were highlighted in depth. Moreover, the positive effects of foods enriched with seaweeds and seaweed extracts on different lifestyle diseases such as obesity, dyslipidemia, hypertension, and diabetes were also discussed. The results of the studies demonstrated that the addition of seaweeds, in powder or extract form, can improve the nutritional and textural properties of food products. Additionally, low-fat products with less calories and less saturated fatty acids can be prepared using seaweeds. Moreover, the addition of seaweeds also affected the health properties of food products. The results of these studies demonstrated that the health value, shelf-life and overall quality of foods can be improved through the addition of either seaweeds or seaweed extracts.