This study explores the efficacy of bamboo essential oil (BEO) incorporated at 15 ppm (T1, BEO-I) and 30 ppm (T2, BEO-II) on the overall physicochemical and oxidative stability, microbial deterioration, and sensory acceptability of meatballs stored for 20 days under refrigerated conditions. Analysis of various parameters, including physicochemical quality, color (CIE L*, CIE a* and CIE b*), generation of oxidative products (TBARS), microbial growth, and sensory acceptability of meatballs were evaluated at 5-day intervals. In addition, the total phenolics and flavonoid content of BEO were estimated, and fatty acids were determined by Gas chromatography (GC.) To gain insights into the biological activities of the BEO, antioxidant assays were determined in vitro using various methods. The antibacterial activity of BEO was also evaluated against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Vibrio cholera, Salmonella Typhimurium, Shigella flexneri, Proteus vulgaris, Escherichia coli and Klebsiella pneumoniae) bacterial strains. The BEO contained a good quantity of total phenolics and flavonoids. In addition, the oil exhibited very potent antioxidant activity scavenging reactive oxygen and other such species, effectively showing IC₅₀ at a very minimal concentration. Further, the BEO exhibited a strong antibacterial effect with MICs within 2 µL and MBCs from 5 to 7 µL for Gram-positive as well as Gram-negative bacteria, respectively. At both the concentrations used, BEO did not show any negative effect on the color of cooked meatballs but rather increased the microbiological and oxidative stability during the overall storage period. Meatballs treated with BEO had considerably reduced oxidative changes in terms of TBARS levels compared to the control. The total viable microbial count was lowest in BEO-treated meatballs and the highest in control. Both control and treated meatballs had a desirable flavor and good acceptability. The sensory attributes and aroma of treated meatballs were better and acceptable during the storage study, whereas the control samples were disliked by the panelists on 15th day. From this study, it can be concluded that bamboo essential oil could be used as a benign and non-toxic preservative to improve the quality and shelf life of cooked meatballs stored under refrigerated conditions.

Terminalia arjuna plant, specially its leaves, bark, and roots, are widely used in traditional herbal medicine due to presence of bioactive components and being a rich source of natural antioxidants. But its fruit has not been used for any such purposes despite its potential to retard oxidation. Hence, the antioxidant potential of Arjuna fruit extract (AFE) in retarding lipid and protein oxidation of raw ground pork was evaluated during refrigerated storage for 9 days. The AFEs were prepared using different solvents viz. ethanol (EH), water, ethanol: water (60:40) and methanol:hot water (60:40). The AFEs were analysed for total phenolic content (TPC), 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity and reducing power. Water extract (WE) and ethanol-water extract (EH-WE) were selected and incorporated at 1.0% into freshly minced pork meat and compared with a synthetic antioxidant, in retarding lipid and protein oxidation during storage. The TPC in AFEs using different solvents ranged from 11.04 to 16.53 mg gallic acid equivalents/g and extracts exhibited appreciable scavenging activity ranging from 50.02% to 58.62%. Arjuna extracts significantly (p<0.05) improved the colour score of meat samples by reducing the formation of metmyoglobin during storage. Both the AFEs (WE and EH-WE) significantly (p<0.05) lowered the thiobarbituric acid reactive substances value, peroxide formation and formation of protein carbonyls in raw pork than control sample during storage. Upon sensory evaluation of all samples, it was found that AFE treatment could prolong the storage period of meat samples, without influencing the colour and odour score, up to 6 days. AFEs used at 1% improved the oxidative stability, colour and odour score and prolonged the refrigerated shelf life of ground pork up 6 days. Therefore, AFE could be explored as an alternative natural antioxidant in retarding lipid and protein oxidation in meat products.

Natural and sustainable plant-based antioxidants and antimicrobials are highly desirable for improving food quality and safety. The present investigation assessed the antimicrobial and antioxidant properties of active components from Alkanna tinctoria L. (herb) roots, also known as Ratanjot root. Two methods were used to extract active components: microwave-assisted hot water (MAHW) and ethanolic extraction. MAHW extract yielded 6.29%, while the ethanol extract yielded 18.27%, suggesting superior Ratanjot root extract powder (RRP) solubility in ethanol over water. The ethanol extract showed significantly higher antioxidant activity than the MAHW extract. Gas Chromatography–Mass Spectrometry analysis revealed three major phenolic compounds: butanoic acid, 3-hydroxy-3-methyl-; arnebin 7, and diisooctyl pthalate. The color attributes (L*, a*, b*, H°ab, C*_ab) for the ethanolic and MAHW extracts revealed significant differences (p < 0.05) in all the above parameters for both types of extracts, except for yellowness (b*) and chroma (C*_ab) values. The ethanol extract exhibited antimicrobial activity against 14 foodborne bacteria, with a significantly higher inhibitory effect against Gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus) than the Gram-negative bacteria (Salmonella enterica serovar Typhimurium and Escherichia coli). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 25 mg/mL for the Gram-negative bacteria, while the MIC and MBC concentrations varied for Gram-positive bacteria (0.049–0.098 mg/mL and 0.098–0.195 mg/mL) and the antimicrobial effect was bactericidal. The antimicrobial activities of RRP extract remained stable under broad temperature (37–100 °C) and pH (2–6) conditions, as well as during refrigerated storage for 30 days. Application of RRP at 1% (10 mg/g) and 2.5% (25 mg/g) levels in a cooked chicken meatball model system prevented lipid oxidation and improved sensory attributes and retarded microbial growth during refrigerated (4 °C) storage for 20 days. Furthermore, the RRP extract was non-toxic when tested with sheep erythrocytes and did not inhibit the growth of probiotics, Lacticaseibacillus casei, and Lactiplantibacillus plantarum. In conclusion, the study suggests that RRP possesses excellent antimicrobial and antioxidant activities, thus making it suitable for food preservation.

The current study investigated the impact of nutmeg essential oil (NEO) and tea tree essential oil (TTEO) on the preservation of raw chicken fillets during nine days of refrigerated storage study. The primary aim was to explore the antioxidant and antimicrobial properties of these essential oils (EOs) and assess their ability to extend the shelf life of poultry meat. Gas chromatography–mass spectrometry (GC-MS) was utilized to identify the chemical compositions of NEO and TTEO, revealing the presence of compounds like myristicin and terpenoids, known for their antimicrobial and antioxidant activities. Antioxidant properties were evaluated using DPPH and ABTS radical scavenging assays, where both oils exhibited potent free radical scavenging abilities, with NEO showing higher efficacy than TTEO. The EOs showed their antimicrobial potential, exhibiting significant antibacterial activities against tested Gram-positive and Gram-negative pathogens, such as Staphylococcus aureus and Escherichia coli, respectively. Raw chicken fillets treated with either NEO or TTEO at 1% were analyzed for physico-chemical, microbiological, and sensory attributes. Results demonstrated that both NEO- and TTEO-treated samples maintained better microbiological qualities, with lower total viable counts and enhanced sensory attributes, such as color and odor, compared to the control samples. Furthermore, NEO and TTEO effectively delayed spoilage, extending the shelf life of chicken fillets by up to seven days. This study concludes that both the test’s essential oils can be considered natural preservatives for enhancing the safety and quality of meat.

Natural and sustainable plant-based antioxidants and antimicrobials are highly desirable for improving food quality and safety. The present investigation assessed the antimicrobial and antioxidant properties of active components from Alkanna tinctoria (herb) roots, also known as Ratanjot root. Two methods were used to extract active components: microwave-assisted hot water (MAHW) and ethanol and air-dried. MAHW extract yielded 6.29% while the ethanol yielded 18.27%, suggesting superior Ratanjot root extract powder (RRP) solubility in ethanol over water. The ethanol extract showed significantly higher antioxidant activity than the MAHW extract. Gas chromatography and mass-spec analysis revealed three major phenolic compounds: Butanoic acid, 3-hydroxy-3-methyl-; Arnebin 7, and Diisooctylpthalate. The color attributes (L*, a*, b*, hab, C*ab) for the ethanolic and MAHW extracts revealed significant differences (P < 0.05) in all the above parameters for both types of extracts, except for yellowness (b*) and chroma (C*ab) values. The ethanol extract exhibited antimicrobial activity against 14 bacterial species, with a signifi-cantly higher inhibitory effect against Gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus) than the Gram-negative bacteria (Salmonella enterica serovar Typhimurium and Escherichia coli). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were both 25 mg/ml for the Gram-negative bacteria, while the MIC and MBC concentrations varied for Gram-positive bacteria (0.049 - 0.098 mg/ml and 0.098 - 0.195 mg/ml) and the antimicrobial effect was bactericidal. The antimicrobial activities of RRP extract remained stable under broad temperature (37-100°C) and pH (2-6) conditions, as well as during refrigerated storage for 30 days. Application of RRP at 1% (10 mg/g) and 2.5% (25 mg/g) levels in a cooked chicken meatball model system prevented lipid oxidation and improved sensory attributes and retarded microbial growth during refrigerated (4°C) storage for 20 days. Furthermore, the RRP extract was non-toxic when tested with sheep erythrocytes and did not inhibit the growth of probiotics, Lacticaseibacillus casei, and Lactiplantibacillus plantarum. In conclusion, the study suggests that RRP possesses excellent antimicrobial and antioxidant activities, thus making it suitable for food preservation.

The adverse effects of chemical preservatives used to prevent food spoilage have led to the search for various biopreservatives. Considering this, a study was undertaken to prepare crude extract (CE) from Indian curd (a fermented dairy product) and characterized it in terms of antioxidant and antimicrobial activities against some common food-borne bacteria. The CE exhibited well pronounced antimicrobial activity against Bacillus cereus and Salmonella typhimurium. The minimum inhibitory concentration (MIC) of CE was recorded for 2-fold concentrated solution prepared from a 10-fold stock. The CE exhibited a significantly higher (p < 0.05) antioxidant and antimicrobial activities compared to its fractions. The CE was found to be heat stable (up to 100 ℃ for 30 min) and exhibited a significant (p < 0.05) increase in activity at pH 2–7 and in combination with 2% citric acid solution. Trypsin treatment suggested it to be of proteinaceous in nature. The antibacterial activity of CE remained intact at 4 ℃ for seven days, whereas non-significant (p > 0.05) changes in its activity were noted during storage at −20 ℃ for 30 days. The curd sample used for preparation of CE, when tested for bacteriocin production and subsequent antimicrobial activity, did not show inhibition against S. typhimurium. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis of CE and its fractions revealed multi-banding pattern. By virtue of its bioactivities observed, CE can be explored as a promising food biopreservative.