Effect Of Preservation Research Articles

Formulating Sustainable Emulsions: Mandelic Acid and Essential Oils as Natural Preservatives.

Emulsion products with natural antimicrobials are becoming increasingly popular for topical application. Mandelic Acid is interesting in cosmetics due to its potent exfoliating properties, which have driven advancements in skincare technologies. Essential oils have various properties, of which the most useful in cosmetics are those that do not cause irritation, smell pleasant, and have other beneficial properties such as antimicrobial effects. Emulsions with Mandelic Acid and essential oils from Satureja montana, Lemongrass, and Litsea cubeba were formulated and microbiologically tested for their preservative effectiveness. The effect of the treatments on skin condition was monitored by non-invasive diagnostic methods, such as hydration, transepidermal water loss, and pH value. Sensory analysis revealed that the matrix containing Mandelic Acid alone or combined with Litsea Cubeba Oil was the best-performing formulation, consistent with the compliant results of antimicrobial efficacy. The topical form of this cosmetic product has demonstrated excellent preservative activity and desirable biophysical efficacy on the skin.

The Impact of Varying Lactose-to-Maltodextrin Ratios on the Physicochemical and Structural Characteristics of Pasteurized and Concentrated Skim and Whole Milk-Tea Blends.

This study investigates the impact of substituting lactose with maltodextrin in milk-tea formulations to enhance their physicochemical and structural properties. Various lactose-to-maltodextrin ratios (100:0, 90:10, 85:15, 80:20, 75:25) were evaluated in both post-pasteurized and concentrated skim milk-tea (SM-T) and whole milk-tea (WM-T) formulations. Concentration significantly improved the zeta potential, pH, and browning index in both SM-T and WM-T compared to pasteurization. L:M ratios of 90:10 and 75:25 in WM-T and 90:10 and 80:20 in SM-T showed higher phenolic preservation after concentration due to structural changes resulting from the addition of maltodextrin and water removal during prolonged heating. The preservation effect of phenolic components in both WM-T and SM-T is governed by many mechanisms including pH stabilization, zeta potential modulation, protein interactions, complex formation, and encapsulation effects. Therefore, optimizing milk-tea stability and phenolic preservation through L:M ratio adjustments provides a promising approach for enhancing milk-tea properties.

Enhanced edible films with Ferulic acid nanoemulsion: Fabrication, characterization, and preservation effects on fresh-cut Chinese water chestnuts

The cavitation produced by ultrasonication can generate strong shear forces and shock waves in the liquid medium, forming nanometer-sized droplets. In this study, ferulic acid (FA) nanoemulsions were prepared using ultrasonication for different durations. The FA nanoemulsion sonicated for 2.5 min exhibited the smallest droplet size (34.44 ± 3.38 nm) and the highest system stability. The compatibility of FA nanoemulsion with gelatin/starch edible films was further analyzed using Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results indicated that the film containing the FA nanoemulsion sonicated for 2.5 min (G/S/FA2.5) demonstrated better film-forming ability, mechanical properties, and barrier performance. Moreover, due to its smallest droplet size and uniform distribution within the film matrix, the G/S/FA2.5 film also showed excellent antioxidant and antibacterial capabilities. Furthermore, the Rheological properties results of the film-forming solution indicate that G/S/FA2.5 possesses a better internal network structure and the most suitable viscosity value for application in food coatings. Finally, the film was applied to fresh-cut water chestnut stored at low temperatures (10 °C). The preservation experiment results showed that the FA nanoemulsion film can suppress up to 50.13% of the yellowing in fresh-cut Chinese water chestnuts by the 8 day of storage, effectively inhibiting the wrinkling on their surface. It significantly reduced the weight loss and spoilage of the water chestnut fruits, thereby extending their shelf life.

Effect of chlorine dioxide (ClO2) combined with different oxygen permeability package treatments on postharvest antioxidant activity and storage life of ‘Liaofeng’ grapes

To enhance the storage quality of ‘Liaofeng’ grapes, this research employed chlorine dioxide in collaboration with different package of preservative bags to explore its preservative effect on ‘Liaofeng’ grapes. After fumigating the grapes with 300 mg L−1 ClO2 solution, the control group was packaged in unpacked and PE bags, while the treatment group was packaged in three kinds of bags with different oxygen permeability, and stored in 4 °C and relative humidity controlled at 90%–95% for 90 days. The results showed that ClO2-GB package treatment significantly delayed the decline of grape hardness (P < 0.05), and decreased the weight loss, threshing, decay and peduncle browning index after storage for 90 days. ClO2-GB package treatment not only diminishes the levels of soluble solids content, titrable acidity, ascorbic acid and glutathione but also effectively suppresses the respiration rate in fruits. The contents of total phenols, flavonoids, anthocyanins and reduced glutathione after ClO2-GB treatment were significantly higher than those in unpackaged group (P < 0.05), and curbed the increase in relative electrical conductivity and malondialdehyde concentration. In comparison to ClO2-YTB and ClO2-YB treatments, ClO2-GB treatment demonstrated superior efficacy in modulating the antioxidant metabolism of grapes. It notably elevated the enzymatic activities of catalase, superoxide dismutase, ascorbate peroxidase, and glutathione reductase, while inhibiting the activities of peroxidase and polyphenol oxidase. The quality assessment of ‘Liaofeng’ grapes after 90 d storage period, conducted through principal component analysis (PCA), yielded the following ranking: ClO2-GB > ClO2-YB > ClO2-YTB > ClO2-PE > ClO2. This suggests that 300 mg L−1 ClO2 fumigation combined with different package treatments was more beneficial to the storage of ‘Liaofeng’ grape. ClO2-GB package treatment emerged as the most advantageous.

Paraben preservatives exhibit inhibition on human and rat steroid 5α-reductase 1: A comprehensive 3D-QSAR and computational analysis

Parabens are preservatives used in personal care products, cosmetics, and pharmaceuticals. Steroid 5α-reductase 1 (SRD5A1) catalyzes the conversion of testosterone to dihydrotestosterone and is present in the brain, contributing to neurosteroid production. This study aimed to assess the effects of nine paraben preservatives on SRD5A1 in human SF126 glioblastoma cell and rat brain microsomes, particularly focusing on dihydrotestosterone production in SF126 cells. The results showed that methyl, ethyl, propyl, butyl, hexyl, heptyl, nonyl, phenyl, and benzyl paraben inhibited human SRD5A1, with nonylparaben having the strongest effect (7.59 μM). Additionally, kinetic analysis indicated that parabens acted as mixed/noncompetitive inhibitors, leading to a significant decrease in dihydrotestosterone production in SF126 cells. While rat SRD5A1 exhibited lower sensitivity to parabens, docking analysis revealed that parabens bind to the NADPH-binding site of both human and rat SRD5A1. In conclusion, these results highlight the inhibitory effects of paraben preservatives on SRD5A1 and elucidate their binding mechanisms, underscoring their role in hormone production.

Study on the preservation effect of 60Co-γ ray irradiation on potatoes

To evaluate the effect of irradiation on the preservation of potatoes, fresh potatoes were selected as the irradiation objects, and irradiated with 60Co-γ radiation source for 0, 100, 200, 500 and 1000 Gy, respectively. During the irradiation, the well-packaged Y1.79Bi0.01Eu0.2MgTiO6 novel thermoluminescence dosimeter material was placed together with the potatoes at the same position. Then, the potatoes were stored in the same temperature and humidity environment, and the quality changes of the potatoes were observed. The Y1.79Bi0.01Eu0.2MgTiO6 material had good performance indicators, and was used to measure the irradiation dose of the potatoes. The experiment showed that irradiation could appropriately extend the storage time of potatoes, and gamma irradiation of about 1000 Gy could achieve the best preservation effect. The main pathogenic fungi that cause dry rot of potatoes were Fusarium solani and Fusarium oxysporum, and the appropriate dose of 60Co-γ irradiation could effectively inhibit the spread and growth of these fungi.

Degradation and preservation of nitrites in whole blood

Understanding the factors that influence nitrite degradation in whole blood and developing methods for its stable preservation are crucial for ensuring accurate and reliable forensic identification in cases of nitrite poisoning. This study systematically monitored nitrite degradation and changes in hemoglobin proportions across different initial nitrite concentrations and blood samples. It was revealed that high nitrite concentrations rapidly reduced deoxyhemoglobin levels within the first 15 minutes and subsequently reacted with oxyhemoglobin at a slower rate. Therefore, the proportions of these two hemoglobin forms are key factors in determining nitrite degradation rates. Regarding preservation, the study examined the effects of low temperatures (4°C and −20°C) and various preservatives (potassium ferricyanide, N-ethylmaleimide) on nitrite stability. The results indicate that adding 6.6 g/L potassium ferricyanide can rapidly eliminate all deoxyhemoglobin and reduce oxyhemoglobin proportions to below 60 %, enabling stable preservation of high nitrite concentrations in whole blood for over 30 days at −20°C. The efficacy of potassium ferricyanide was further validated in forensic-acquired postmortem heart blood samples.

Practical 1-Methylcyclopropene Technology for Increasing Apple (Malus domestica Borkh) Storability in the Aksu Region.

In recent years, Aksu apple has become popular with consumers because of its unique texture and taste. At present, maintaining quality during storage is the key problem with the apples in the Aksu region. 1-Methylcyclopropene (1-MCP) can delay fruit senescence, so is widely used in fruit preservation. However, many factors affect the preservation effect of 1-MCP. The effects of 1-MCP concentration (0 µL·L-1, 1 µL·L-1, 3 µL·L-1, 5 µL·L-1, and 8 µL·L-1) and postharvest application time (0, 1 and 2 d after harvest) on the quality of stored apple were studied. It was found that 1 µL·L-1 1-MCP was more beneficial in improving the quality of stored apples, reduced the respiration intensity and decay rate, increased the fruit firmness and total soluble solid content, and reduced the relative content of ester volatile aroma components. In addition, 1-MCP treatment applied at different postharvest times also affected the sensory quality and flavor of apples. The effect of 1-MCP treatment immediately after harvest was better.

The Evaluation and Analysis of the Anti-Corrosion Performance of the Sealing Material B72 for Metal Artifacts Based on Electrochemical Noise

Paraloid B-72 (B72), as a transparent, colorless polymer material, has good film-forming ability when dissolved in acetone and is widely used as a sealing material for metal artifacts. In order to analyze and evaluate the preservation performance of B72 as a sealing material on the substrate of metal artifacts, a variety of electrochemical methods, mainly electrochemical noise (EN), and scanning electron microscopy (SEM) were applied to evaluate the B72 coating. The results showed that the B72 coating had a good preservation effect at the initial stage, and its poor water resistance led to the loss of its effectiveness after a few days of immersion. Compared with conventional electrochemical methods, electrochemical noise is non-destructive, which cannot cause new corrosion on the metal substrate and can well characterize the corrosion rate of the test system, and the results of its time domain and frequency domain analyses can correspond well with the polarization resistance and impedance spectra. Electrochemical noise is an effective method for evaluating the anti-corrosion performance of material preservation coatings.

Assessing the Preservation Effectiveness: A Comparative Study of Plasma Activated Water with Various Preservatives on Capsicum annuum L. (Jalapeño and Pusa Jwala)

The study investigates the efficacy of plasma-activated water (PAW) in preserving green chillies (jalapeño and pusa jwala) and compared it with various household fruits and vegetables cleaners’ solutions. PAW was prepared using a pencil plasma jet with air as the plasma forming gas. The results of visual analysis revealed that PAW-treated chillies maintain their fresh appearance even after 21 days, exhibiting significantly lower spoilage compared to control (ultrapure milli-Q water) and fruits and vegetables cleaners’ solutions. PAW demonstrated antimicrobial properties, effectively reducing microbial growth and spoilage on chillies over the storage period. Physical attributes, such as weight loss and firmness, are evaluated. It has been observed that PAW-treated chillies exhibit lower weight loss and higher firmness, indicating better membrane integrity and moisture retention. Microbial resistance was notably higher in PAW-treated chillies compared to control and when cleaning solutions were used. CIELAB color analysis revealed that PAW-treated chillies retain greenness, and color, freshness, outperforming control and cleaners. Sensory evaluation, including visual inspection, smell, taste, and touch, consistently favored PAW-treated chillies, emphasizing their superiority in terms of enhancement in shelf-life. Biochemical analysis revealed that PAW-treated chillies either maintain or show enhancement in nutritional attributes such as soluble sugar, protein, and ascorbic acid concentrations. Phenol concentration (antioxidant activity) remained stable across treatments. Overall, the study underscores the positive impact of PAW treatment on preserving the membrane integrity, antimicrobial resistance, sensory quality, and nutritional attributes of green chillies, making PAW an alternative for extending their shelf life.

The preservative effect of the black rice's cold, hot and ultrasonic ethanol extracts on the storage quality of beef patties

SummaryThis work aimed to determine the total anthocyanin and phenolic contents and antioxidant capacity of extracts of the black rice's cold, hot and ultrasonic‐assisted extracts and their preservative effect on the storage quality of beef patties. The three extracts exhibited high anthocyanin, phenolic content and antioxidant capacity, and they were used in beef patties at five treatments (negative control without extract, positive control with 0.01% butylated hydroxytoluene (BHT), 7.5% cold extract, 7.5% hot extract and 7.5% ultrasound‐assisted extract). Raw and cooked beef patties were tested at 0, 3, 6, 9 and 12 days of cold storage in aerobically packaged polyethylene containers regarding pH, oxidative stability, antioxidant capacity and microbial quality. While adding black rice extracts did not influence the proximate composition of raw samples (P &gt; 0.05), it slowed down the pH and lipid oxidation during storage and provided pH and thiobarbituric acid reactive substances (TBARS) stability in all final products. The BHT and treatments with extract indicated a higher 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) value than the negative control. Also, the incorporation of black rice extracts slightly retarded bacterial growth. These results suggest that the black rice extracts at 7.5% can be used effectively to protect beef patties from microbial spoilage and oxidation during cold storage for 12 days.

Seismic shear wave noise suppression and application to well tie

Abstract Seismic shear waves have been employed in oil and gas exploration for decades. A 2D seismic shear wave inline was acquired in Sanhu area, located in the Qaidam Basin in western China. Although the acquired shear wave data exhibits high resolution and comparable bandwidth to the compressional wave, it is contaminated by various types of noise, including linear noise, single-frequency noise, and especially internal multiples. Internal multiples seriously compromise the primary reflections at both near-offset and far-offset and are difficult to be suppressed. This paper presents a case study of noise attenuation for the seismic shear wave. Firstly, single-frequency noise and linear noise are attenuated through filtering methods. Then, two methods (the Radon transform and the frequency-wavenumber (F-K) filtering) are evaluated for their effectiveness in multiple suppression and amplitude preservation. The results indicate that both methods successfully reduce long-period multiples at far-offset, enhancing the signal-to-noise ratio. We show that F-K filtering retains the characteristic ‘strong-weak-strong’ amplitude variation in the SV-SV wave data gather, making it preferable for subsequent AVO (amplitude variation with offset) analysis and inversion. Finally, a wave-equation-based MSI (multiple suppression inversion) method is used to suppress near-offset internal multiples. This involves iteratively predicting internal multiples and adaptively subtracting them from the original data. Stacked sections of different offsets are compared to demonstrate de-multiple result, and the result is also validated by the improvement of well calibration with the seismic shear wave data.

Effect of Near-Freezing Storage Combined with High-Voltage Electric Fields on the Freshness of Large Yellow Croaker.

Seafood is highly perishable after being caught, making effective preservation technology essential. A few studies have explored the mechanisms of near-freezing storage combined with high-voltage electric fields for seafood preservation. This study uses near-freezing storage at -1 °C in conjunction with three high-voltage electric fields (5 kV/m, 8 kV/m, and 16 kV/m) to store large yellow croakers for 21 days and assesses their quality through sensory evaluation, pH values, malondialdehyde, total volatile basic nitrogen, and total viable counts. The results indicate that high-voltage electric fields effectively inhibit endogenous enzyme activity and microbial growth while reducing lipid oxidation in large yellow croakers. The preservation effect is optimal at an electric field strength of 16 kV/m, extending their shelf life by 9 days. These findings offer valuable theoretical and data-driven insights for applying near-freezing storage and electric field preservation technology in cross-regional fish transportation.

The effect of three different preservatives on the numbers and types of bacteria, Brix percentage, pH and nutritional composition of bovine colostrum sourced from New Zealand dairy farms

ABSTRACT Aims To investigate the effect of preservation by addition of yoghurt starter, potassium sorbate and citric acid on counts of aerobic bacteria, Lactobacillus spp., Streptococcus thermophilus and coliforms, Brix percentage, pH, protein, fat and anhydrous lactose concentrations at 0, 7 and 14 days after collection for colostrum stored at ambient temperature. Method Approximately 2 L of first milking colostrum was collected from 10 farms in the Waikato region. Following mixing, it was split into five 400-mL sub-samples and allocated randomly to a control (two sub-samples), or treatment with yoghurt, potassium sorbate, or citric acid preservative. Throughout the trial samples remained in the laboratory at ambient temperature with the lids slightly ajar, and were stirred daily for 15–30 seconds using a sterile spatula. Sub-samples were tested on Days 0, 7 and 14. On Days 0 and 14 aerobic bacteria (by aerobic plate count (APC)), Lactobacillus spp., coliforms and Streptococcus thermophilus counts, pH, Brix percentage, protein, fat and anhydrous lactose were measured. On Day 7 only bacterial counts were completed. The data were analysed using non-parametric clustered bootstrap sampling to estimate the effect of treatment, time, and their interaction on the outcome variables. Results Compared to control samples, on Day 7 the APC for potassium sorbate (1.0 (90% CI = 0.6–1.6) × 108 cfu/mL) was approximately seven-fold lower than for yoghurt (7.3 (90% CI = 4.1–11) × 108 cfu/mL), and approximately three-fold lower than citric acid (3.2 (90% CI = 0.2–4.3) × 108 cfu/mL) remaining low to Day 14. All preservatives reduced coliform growth compared to control samples at Day 7 but growth was lower for potassium sorbate than the other preservatives. For Lactobacillus spp., at Day 7, samples with yoghurt preservative had greater counts than the other two preservatives. Potassium sorbate reduced growth of S. thermophilus compared to the other treatments, especially at Day 7, with 7–10 times fewer S. thermophilus per mL compared to the other three groups. All groups showed an obvious acidification over time, with very little variation within days and treatment groups. There was no evidence for change in fat or protein percentage over time regardless of treatment. Conclusion and clinical relevance Aerobic and coliform bacteria proliferate extensively in unpreserved colostrum. All preservatives decreased coliform counts compared to un-preserved colostrum, but potassium sorbate was more effective at decreasing both coliforms and aerobic bacteria than either yoghurt or citric acid.

Improved post‐harvest preservation effects of mushroom (Agaricus bisporus) using bacterial cellulose nanocrystals‐gelatin/cinnamon essential oil emulsion coatings

SummaryThis work investigated the effect of bacterial cellulose nanocrystals (BCNCs)‐gelatin (GelA)/cinnamon essential oil (CEO) emulsion coatings (BCNCs‐GelA/CEO) on the shelf‐life extension of button mushrooms (Agaricus bisporus). CEO loadings between 1200 and 2400 μL/L were used in the coatings applied on the mushrooms' surface. The overall quality of coated mushrooms was monitored over 15 days of cold storage (4 ± 0.5 °C). Regardless of the storage time, using the highest amount of CEO within the coating formulation minimised the impact on tested parameters (weight loss, firmness, percentage of opened caps, total soluble solids, content of ascorbic acid and soluble protein, PPO/POD enzymatic activity) as compared to control samples. Interestingly, a linear relationship (R2 = 0.96 on average) between CEO concentration and the respiration rate of coated mushrooms was disclosed. Overall, this study pinpointed the capability of BCNCs‐GelA/CEO coatings to delay the aging process of button mushrooms under cold storage. Our findings could be applied to address the issue of food losses, highlighting the positive role of coating technology in enhancing the efficiency of the early stages of the food supply chain, especially in the case of button mushrooms. However, an assessment of the impact of the concentration of other coating components (BCNC and fish gelatin) on the shelf‐life extension of button mushrooms, as well as an evaluation of the coating's effectiveness in prolonging the shelf‐life of other food items, particularly non‐respiring products, is necessary to widespread the applicability of the proposed technology.

Exploring the potential of cold plasma in Optimising quality and boosting antioxidant defence in fresh‐cut bamboo shoots

SummaryCold plasma (CP) is a promising technology for fresh‐cut fruits and vegetables. In this study, the effects of CP on postharvest senescence, especially from the perspective of oxidative response of fresh‐cut bamboo shoots were examined, including the colour, firmness, lignin content, reactive oxygen species (ROS) accumulation and antioxidant enzymatic activities. CP treatments delayed the browning of bamboo shoots indicating by the increase of L* and b* values and decrease of a* value. The browning inhibition coincided with the reduction of PPO activities up to 62% by CP at 20 kV. Cellulose and lignin accumulated during storage. CP at 30 kV accelerated lignification, whereas CP at 10 and 20 kV inhibited the increase. These results were also reflected by PAL, CAD and POD activities that were enhanced by CP at 30 kV and inhibited by CP at 10 and 20 kV. The content of O2− and H2O2 was significantly increased at the first 3 days and decreased afterwards, with a similar trend of antioxidant enzymes SOD and CAT. As smaller increases in H2O2 and O2− production in CP treated samples than in control were probably attributed to elevated CP‐induced SOD activity. In addition, there was a delay effect observed in the internal parts of bamboo shoots compared with the surface (&lt;5 mm thick). CP extended the shelf‐life of bamboo shoots by triggering the antioxidant defence. CP at 20 kV exhibited the best preservative effect on fresh‐cut bamboo shoots.

Influence of Tea Polyphenols, Chitosan, and Melatonin as the Eco-Friendly Post-Harvest Treatments on the Vase Life of the Cut Chrysanthemum ‘Pingpong’ Group

Vase life is a decisive measure of the marketability of post-harvest physiology in cut flowers. In the process of petal senescence, the cut chrysanthemum (Chrysanthemum × morifolium) ‘Pingpong’ group develops severe capitulum collapse which manifests as wilting and browning, leading to shorter vase life. Melatonin (MT), tea polyphenols (TPs), and chitosan (CT) are natural alternatives to chemical compounds with proven preservation effects. In this study, the possibility of mitigating capitulum collapse using the preservation solutions of these three eco-friendly ingredients was investigated on four varieties from the ‘Pingpong’ group, aiming to delay the senescence process. The effects on vase life of 0.02/0.04 mmol·L−1 MT, 200/400 mg·L−1 TPs, and 0.10/0.20 g·L−1 CT were, respectively, assessed with the basis of 20 g·L−1 sucrose and 250 mg·L−1 citric acid. The yellow and white varieties tend to have a longer vase life compared with the green and pink varieties. Compared to the control with only base ingredients, the greatest delay in capitulum collapse was observed with 0.04 mmol·L−1 MT in the yellow variety, maximizing the vase life to 13.4 days. MT maintained the best ornamental quality of the capitulum by decelerating fresh weight and flower diameter loss in terms of all varieties. TPs significantly increased flower diameter to improve vase life up to four more days. However, CT caused significant negative effects on vase life, with severe loss of both flower diameter and fresh weight. Therefore, the application of 0.04 mmol·L−1 MT and 200 mg·L−1 TPs was suggested to enhance the marketability of cut ‘Pingpong’, which highlighted the eco-friendly potential of post-harvest treatments.

Waste management of multiple food products through IoT enabled preservation policies and secondary supply chains

Recycling food waste (FW) into secondary products can transform the waste-to-value. This study proposes reducing FW through IoT controlled preservation and consuming it through a secondary supply chain (SSC). It explores the best policies for SSC management that recycles FW. The food chain comprises of multiple food processors for preparing multiple food products, and a common retailer where IoT based preservation curtails food deterioration. The SSC consumes the FW by recycling into multiple secondary products at multiple recycling plants and retailing at a secondary retailer. A dual channel waste collection viz. from retailers and consumers is maintained. Each product within primary and secondary supply chains (PSSCs) has a different lifetime, rate of deterioration (RoD), and preservation effectiveness. A nonlinear mathematical model is presented that optimizes decision-making for maximizing profitability. Outcomes of computational experiments demonstrate that the SSC removes 100% of the FW, conserves 89% of material resources, reduces 16% of the total cost, minimizes preservation efforts by 50%, improves replenishment cycle, and increases profitability by 39%. Some managerial insights are provided for making vital supply chain decisions.

Comparative Evaluation of Change in Organoleptic, Proximate and Vitamin Content of Freshwater Fish Species, Heteropneustes fossilis at Various Duration of Low Temperature Preservation

The present study was conducted to evaluate the effect of low temperature preservation on the sensory characteristics, proximate and vitamin content of freshwater fish species, Heteropneustes fossilis. Samples prepared from the fish were kept in low temperature for different duration and nutritional parameters were analyzed. The values of proximate composition of the sample showed the highest content for the fresh sample and the values tend to decreased with increasing storage duration except for carbohydrate. Among all the proximate parameters, moisture, protein, lipid and ash showed a content decreased during storage. However, carbohydrate showed the opposite trend, increased with storage duration. Again, among all the fat soluble vitamins, sample showed the highest value for vitamin D and lowest for vitamin E. Vitamins also showed the declining trend with increasing storage duration. From the present results, it can be stated that fresh fish sample had the highest nutrient content, therefore they should be preferably consumed over preserved fishes or if preserved, it should be for a shorter duration of time so that its nutritional content retains the same.

Effect of selective preservatives on shelf-life of guava juice extracted using pectinase enzyme

The study investigated the feasibility of enzymatic extraction for guava juice and evaluated the effects of various preservatives on its shelf life. The crushed guava puree was undergone different pectinase enzyme concentrations over three incubation periods. The findings revealed that pectinase concentrations of 0.1 % and 0.2 %, when incubated for 1 and 2 h, were the most effective. Juice yields ranged from 65.24 % to 78.64 %, with Total Soluble Solids (TSS) varying from 9.12°Brix to 11.56°Brix. The physicochemical properties of the guava juice resulted 84.2 % moisture, 2.16 % protein, 0.77 % fat, 3.27 % fiber, 0.65 % acidity, 2.25 % reducing sugars, 8.27 % non-reducing sugars, 79.53 % antioxidant activity, 173.2 mg/100g of ascorbic acid, 10.52 TSS, 109.7 mg/100g of phenolic content, and a pH of 3.2. Eight juice samples were prepared as per formulation with sodium benzoate and potassium metabisulfite (KMS) at concentrations of 150 ppm, 200 ppm, and 250 ppm, in addition to one refrigerated sample and one control. The stability of these guava juice samples was monitored every 15 days over a 90-day period. Results showed that acidity, TSS, pH, reducing sugars, and non-reducing sugars changed over time. Samples with preservatives exhibited slower changes compared to the control. Phenolic compounds diminished more quickly at ambient temperature than in refrigerated or preservative-treated samples. Initially, phenolic content and antioxidant capacity were 44 mg GAE/100g and 44 %, respectively, but declined to 10–15 mg and 15–17 % by the end of the storage period. Color changes were more noticeable in samples stored at room temperature, whereas preservatives effectively reduced color degradation caused by enzymatic browning. Moreover, ascorbic acid retention was better in samples with preservatives and those stored under refrigeration. The ascorbic acid degradation rate was highest at room temperature (0.023 day^-1) and lowest with 250 ppm KMS (0.016 day^-1). Microbiological tests indicated that the juice remained safe for 40 days at room temperature, 90 days under refrigeration, and approximately 85 days with preservatives.