Changes in quality of rainbow trout (Oncorhynchus mykiss) fillets preserved with salt and sugar at low concentrations and stored at 4°C

The effects of dry-curing with low concentrations of salt and sugar on the quality of rainbow trout (Oncorhynchus mykiss) fillets were studied over a 16-day storage period at 4°C. Physicochemical characteristics (total volatile base nitrogen (TVB-N), biogenic amines (BAs), ATP-related compounds and K value), microbial populations (total aerobic counts (TAC), H₂S-producing bacteria, Pseudomonas, Aeromonas, and lactic acid bacteria) and sensory (SA) indicators were analyzed. Fish samples were subjected to the following treatments: untreated (control), dry-cured with 1.3% salt (T1), and dry-cured with 1.3% salt that also contained 0.9% sugar (T2). SA indicated that the sensory quality of the control, T1, and T2 was unacceptable after 8, 12, and 12 days of storage, respectively. Moreover, the cadaverine concentration of treated samples was significantly lower (P < 0.05) than the control after storing for 8 days. T1 and T2 were significantly higher (P < 0.05) than the control in inosine 5-monophosphate (IMP) content from the 2th to 10th day. Cadaverine, putrescine, hypoxanthine, and TAC were correlated significantly (P < 0.01) with SA, and these seemed to be reliable indicators of fish quality. The results indicated that curing treatments extended the shelf life of rainbow trout fillets, which could be exploited by processors.     

Changes in quality attributes of pulsed light and thermally treated mixed fruit beverages during refrigerated storage (4 °C) condition

The effect of batch pulsed light (PL) irradiation (3000 J cm⁻²) on the shelf-life of the beverage blend comprising apple ber (Indian jujube), carambola (star fruit), and black table grapes was investigated. The equivalent thermally treated beverage (90 °C|5 min) exhibited greater stability from microbial and enzymatic spoilage but retained 27% less antioxidants and 14% less vitamin C than PL-treated juice. Thermally and PL-treated blends possessed sensory scores of 5.8 and 7.2, respectively. The beverage's microbial shelf-life (population ≤ 6-log₁₀ cfu/mL) was extended to 45 days at 4 °C after the PL treatment. The PL exposure did not alter the pH and soluble solids during storage. The PL-treated juice, after 45 days, was placed on par with the freshly prepared juice by the sensory panel. The PL-treated juice preserved 61% more antioxidants, 38.8% more phenolics, and 68.2% more vitamin C than the thermally pasteurized beverage after 45 days of refrigerated storage.Industrial relevanceWhile the fruit processing industry demands microbial safety and enzymatic stability, today's consumer demands juices of high nutritional quality. This study utilizes under-explored fruits like apple ber (Indian jujube) and carambola (star fruit) to make a shelf-stable mixed fruit beverage. This study will help the industry understand the potential of PL treatment in accomplishing microbial safety, enzymatic stability, and nutritional quality, along with the utilization of under-explored fruits.     

Enhancement of γ-aminobutyric acid content in shells of passion fruit (Passiflora edulis) under anoxic vacuum conditions

Passiflora edulis, commonly known as passion fruit, is a popular all-weather fruit eaten fresh or processed. Its shells, which currently are mostly discarded as waste and hurt the environment, account for more than half of the passion fruit. The shells contain gamma-aminobutyric acid (GABA) which is the main inhibitory neurotransmitter and has many proven medical values such as antidepressant, anti-anxiety, etc. Many studies have shown that GABA production in plants can be significantly increased by reverse stress. Taking Tainong 1 as a typical passion fruit cultivar, this study explored the optimal anoxic vacuum treatment for increasing the GABA content of passion fruit shells. The content increased to 2139.25 ± 26.69 mg/100 g on day 4 of chill storage after vacuum packing (63.68% higher than the control). The activities of glutamate decarboxylase (GAD) and diamine oxidase (DAO) were significantly higher in the vacuum-treated group than in the control group after 4 days of vacuum-chill storage. On day 5 of vacuum-chill storage, the activities of all measured enzymes decreased except for the increase of GABA transaminase (GABA-T), which was accompanied by a decrease in GABA content. Vacuum treatment and subsequent chill storage increased the content of GABA, thereby increasing functional value of passion fruit shells.     

Effect of dipping in pomegranate (Punica granatum) fruit juice phenolic solution on the shelf life of chicken meat under refrigerated storage (4°C)

An experiment was conducted to evaluate the effect of dipping in pomegranate fruit juice phenolics (PFJP) solution on the shelf life of chicken meat held under refrigerated storage at 4°C. Breast muscle obtained from spent hens was dipped (1:2w/v; muscle: liquid) in sterile water or in sterile water with 0.02% (v/v) PFJP, packed, stored at 4°C for 28 days and samples were analyzed on 2 days of intervals. Thiobarbituric acid reactive substance values were lower in samples treated with PFJP. Total sulfhydryl and protein bound sulfhydryl content values were higher in samples treated with PFJP. Microbial quality evaluation showed that aerobic and psychrotrophic counts were higher in samples treated without PFJP. Sensory evaluation revealed that acceptability level of samples treated without PFJP decreased on 12th day of storage. It is concluded that spent hen breast meat samples dipped in 0.02% PFJP reduced protein oxidation and inhibited microbial growth and sensorily acceptable up to 12 days of refrigerated storage at 4°C.     

The impact of chitosan film or chitosan/chitosan–epigallocatechin gallate conjugate composite film on the quality changes of Asian sea bass (Lates calcarifer) slices stored in air or under vacuum packaging

Quality and shelf-life of Asian sea bass slices (ASBS) wrapped with chitosan (CS)/CS–epigallocatechin gallate (CE) conjugate composite or CS films and packaged in air or under vacuum during storage at 4 °C were studied. Total viable count was less than permissible limit (6 log·CFU g⁻¹ sample) for ASBS wrapped with CS/CE conjugate composite film under vacuum (ASBS-COMP-VP) after 18 days. Moreover, lower microbial proliferation and volatile base contents were attained in ASBS-COMP-VP sample than other samples during the storage (P < 0.05). At the end of storage, ASBS-COMP-VP sample had lower lipid oxidation than those wrapped with CS film (P < 0.05). Polyunsaturated fatty acid content of ASBS-COMP-VP was retained at higher content at day 18. Therefore, ASBS-COMP-VP had the enhanced shelf-life with high acceptability up to 18 days at 4 °C, while ASBS wrapped with CS film and packaged in air or under vacuum had the shelf-life of 9 and 12 days, respectively.     

Chemical characterization and antioxidant capacity of the araçá-pera (Psidium acutangulum): An exotic Amazon fruit

The “araçá-pera” (Psidium acutangulum DC) is an exotic guava consumed by the Brazilian Amazon population. This paper describes 22 compounds from this fruit by UHPLC–HRMS and NMR methods, being one disaccharide, five monosaccharides, two organic acids, one trihydroxycinnamic acid glucopyranosyl, one tannine digalloyl glucopyranosyl, five triterpenoid acids, and six fatty acids. It also quantifies the level of ascorbic acid (AA) by HPLC–MS (74.32 ± 1.23 mg/100 g of fresh fruit), and defines the chemical antioxidant activities by DPPH and ABTS⁺ assays (24.96 ± 0.75, 90.57 ± 0.63 mg of vitamin C/100 g fresh fruit, respectively), and a cell-based assays (76–100%). These results have shown that this exotic guava can be consumed as a nutraceutical ingredient, as well as be used in the production of functional foods in the Amazonian diet to prevent chronic and oxidative diseases.     

SmartStretch™ technology: V. the impact of SmartStretch™ technology on beef topsides (m. semimembranosus) meat quality traits under commercial processing conditions

This study evaluated the effect of SmartStretch™ technology and ageing on meat quality traits of hot-boned beef m. semimembranosus from cull cows. The technology uses a flexible rubber sleeve surrounded by inflatable bladders that are housed within an airtight chamber. The sleeve is expanded allowing the meat to be inserted. Air is then pumped into the inflatable bladders causing the meat to be compressed by force and ejected into packaging. No significant treatment effect (P > 0.05) on shear force was found although ageing did significantly reduce shear force (P < 0.001). There was a significantly greater (P < 0.05) cook loss at 14 days, but less (P < 0.05) thaw loss and purge with 0 day cook loss unaffected (P > 0.05). Sarcomere length examined by both laser diffraction and a filar micrometre method was significantly increased (P < 0.05) following the treatment although a proportion of individual myofibrils appeared to have short and long sarcomeres.     

Evaluation of the antioxidant,antiproliferative and antimutagenic potential of araçá-boi fruit (Eugenia stipitata Mc Vaugh — Myrtaceae) of the Brazilian Amazon Forest

Eugenia stipitata is a fruit from Amazonia rich in terpene, volatile compounds, fiber, and vitamin C. The fruit is recognized for its high antioxidant activity and has attracted much attention due to their potential health benefits to humans. The total polyphenols, antioxidant, antiproliferative, antimutagenic and antigenotoxic activities of E. stipitata ethanolic extract were investigated. Total polyphenols were determined by the Folin–Ciocalteu method and showed 184.05 ± 8.25 mg GAE/100 g. The radical scavenging activity was DPPH _IC50 0.69 ± 0.23 μg/mL and TAC-ORAC_FL 371.98 μmol.TE/100 g. The extract was evaluated for its ability to inhibit the growth of tumor cell lines and had not complete cystostatic effect against any of the tested cell lines. Antimutagenic and antigenotoxic activities were investigated by micronucleus test and comet assay in mice, respectively. Ethanolic extract of E. stipitata showed higher antimutagenic and antigenotoxic properties at the highest concentration tested (300 mg/kg of body weight). In conclusion, these results suggest that this fruit could be used as a preventive agent against cancer.     

SmartStretch™ technology. IV. The impact on the meat quality of hot-boned beef rostbiff (m. gluteus medius)

The impacts on traits of the m. gluteus medius hot-boned from young cattle were assessed after stretching (SmartStretch™) and ageing (0 or 8 days ageing). Tenderness, as reflected in reduced shear force measurement, was significantly (P < 0.05) improved in 0 day aged stretched samples over the un-stretched control. After 8 days ageing there was no longer a difference in the tenderness between stretch treatments. Meat aged for 8 days was significantly more tender than 0 day aged meat irrespective of treatment. Sarcomere length was significantly (P < 0.05) increased by stretching. There was a significant (P < 0.05) negative relationship between sarcomere length and shear force. Presentation traits, such as purge loss and fresh colour, were unaffected by the stretch treatment, while cooking loss was significantly (P < 0.05) reduced by stretching in the 0 day aged samples.     

Interaction of phosphatidylcholine and α-tocopherol on the oxidation of sunflower oil and content changes of phosphatidylcholine and tocopherol in the emulsion under singlet oxygen

Abstract: Interaction of phosphatidylcholine (PC) and α‐tocopherol (α‐Toc) on the oxidation of oil in the emulsion consisting of sunflower oil and water under singlet oxygen at 25 °C was studied by determining peroxide value (PV) and conjugated dienoic acid (CDA) contents. Singlet oxygen was produced by chlorophyll b under 1700 lux. Single addition of PC or α‐Toc decreased the values of peroxides and CDAs of oil in the emulsion via singlet oxygen quenching. PC and α‐Toc showed simply additive interaction in decreasing the singlet oxygen oxidation of oil in the emulsion. α‐Toc was a physical quencher of singlet oxygen in the emulsion, but PC involved chemical quenching in the antioxidant action. Chlorophyll and PC contents were decreased in the emulsion under singlet oxygen, while α‐Toc was not. α‐Toc protected chlorophyll and PC from degradation, and was a more important component than PC in the oil oxidation under singlet oxygen in the emulsion.     

The role of 2-hydroxypropanal in the biosynthesis of 2,5-dimethyl-4-hydroxy-2H-furan-3-one in strawberry (Fragaria × ananassa,cv. Elsanta) callus cultures

2-Hydroxypropanal was synthesized utilising a new approach via the Curtius rearrangement, which has the great advantage that the only co-product is ammonium chloride. 2-Hydroxypropanal was, without isolation, fed in situ to strawberry callus cultures in order to study the biosynthesis of 2,5-dimethyl-4-hydroxy-2H-furan-3-one. The high levels of the furanone obtained suggest that 2-hydroxy-propanal is a key precursor of 2,5-dimethyl-4-hydroxy-2H-furan-3-one in strawberry.