Potassium Metabisulphite Research Articles

Comparative assessment of fresh and processed tomato (Solanum lycopersicum) pulps: Impact of processing on physicochemical, antioxidant, and enzymatic behavior

This study investigated the impact of chemical and thermochemical treatment on the physicochemical, antioxidant, and enzymatic behavior of tomato pulp. The chemical treatment involved the use of 0.05 % potassium metabisulfite, 0.05 % sodium metabisulfite, 0.05 % potassium sorbate, 0.05 % sodium benzoate, 0.5 % ascorbic acid, and 1 % citric acid, whereas the thermochemical treatment involved heating the tomato pulp to 80–82 °C for 30 min before applying the same chemical preservatives, followed by storage at 30±1 °C for 120 days. The results revealed that the thermochemically treated sample retained higher levels of total phenol content (6.24–4.10 mgGAE/100 g), vitamin C (136.43–54.05mg/100 g), and a lower level of lycopene content (59.87–43.28µg/100 g) compared to chemically treated samples. Additionally, the thermochemically treated sample had higher TSS (6.57 to 6.70°Brix), increased acidity (1.60 % to 1.06 %), lower pH (4.11–3.57), better color stability, and reduced browning. Moreover, it showed improved oxidoreductase and hydrolase enzymatic control during storage. Therefore, the idea of thermochemical treatment can be a milestone in improving the shelf life of tomato pulp to benefit the food industry.

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.

Nutritional retention and browning minimisation in dehydrated onion slices through potassium metabisulphite and sodium chloride pre‐treatments

SummaryThe global demand for dehydrated onion is on the rise, driven by the increasing consumer preference for ready‐to‐eat convenience foods. This study focused on enhancing the quality and functional properties of dehydrated onion slices (cv. Pusa Shobha) through different pre‐treatment and drying conditions. Fresh onion slices were subjected to pre‐treatment using NaCl (3%, 5% and 7%) and KMS (0.3%, 0.5% and 0.7%) solutions for 10 min, followed by tray drying at 50 °C, 60 °C and 70 °C temperatures for varying durations of 14, 12 and 10 h, respectively. Based on physicochemical and functional properties, onion slices pretreated with 5% NaCl + 0.5% KMS and dehydrated at 60 °C for 12 h retained higher bioactive compounds like total phenols (166.32 mg GAE 100 g−1 DW), total flavonoids (28.94 mg QE g−1 DW), ascorbic acid (12.45 mg 100 g−1 DW), quercetin (172.88 μg g−1 DW) and total antioxidant activity (24.59 μmol TE g−1 DW). Additionally, it maintained superior sensory acceptability with higher pungency (7.15 μmol g−1 DW), dehydration ratio (9.25%), rehydration ratio (5.20%), lower non‐enzymatic browning (0.36) and moisture content (5.75%). Hence, the optimised treatment of ‘Pusa Shobha’ slices with 5% NaCl + 0.5% KMS, followed by dehydration at 60 °C for 12 h, yields dehydrated onion slices with superior bioactive compounds, sensory acceptability, and enhanced functional properties. The findings of his research offer valuable technology for the food industry, providing a practical and efficient method to produce high‐quality dehydrated onion slices.

Effect of Potassium Metabisulphite and Modified Atmosphere Packaging on Shelf Life of Pink Oyster Mushroom (Pleurotus eous)

Effect of Potassium Metabisulphite and Modified Atmosphere Packaging on Shelf Life of Pink Oyster Mushroom (Pleurotus eous)

Efficiency of Ozone Quenching Agents at Different Temperature, pH, and Hydrodynamic Conditions

ABSTRACT Quenching of excess aqueous ozone (O3) residual is needed to avoid off-gassing and oxidative damage to downstream components. Eight quenching agents (QAs), calcium thiosulfate (Ca-Thio), sodium bisulfite (Na-Bi), hydrogen peroxide (H2O2), sodium thiosulfate (Na-Thio), sodium metabisulfite (Na-Metabi), potassium metabisulfite (K-Metabi), sodium sulfite (Na-S), and ascorbic acid (AscAcid) were tested at varying pHs (7.5, 7.9, and 8.5) and temperatures (4°C, 15°C, and 23°C). Temperature had significant effects on initial quenching (≤30 s), with less occurring at 4°C than 23°C; but with extended contact time this trend reversed. Quenching efficiency was not substantially affected by pH. Ca-Thio and Na-Thio were inefficient but quick, had lower mass requirements, and minimal handling concerns. Na-Metabi, Na-Bi, and Na-S were quick and efficient, but K-Metabi was the only QA that quenched (26–31%) less O3 than stoichiometry at all conditions. These sulfite-based QAs had more handling concerns and greater mass requirements. H2O2 was slower than other QAs but 2–9× quicker than predicted by rate coefficients and efficient when given longer contact time (≤5 min). H2O2 had some handling concerns but the lowest mass requirements (assuming 5 min contact time) and creates desirable AOP conditions. AscAcid consistently quenched (22–113%) more O3 than the stoichiometric ratio but had higher mass requirements, except in colder temperatures. Hydrodynamics, QA-diffuser design, and supply chain were also important considerations.

Convective drying of bitter yam slices (Dioscorea bulbifera): Mass transfer dynamics, color kinetics, and understanding the microscopic microstructure through MATLAB image processing

The objective of this research endeavor was to enhance the quality and storability of Dioscorea bulbifera through the investigation of the effects of pre-treatment (soaking) and different dehydration temperatures (50, 60, and 70°C) on its mass transfer, color kinetics, texture, microstructure, and rehydration properties. Ten drying and four-color kinetics models were employed to describe drying behavior and color changes. The drying process demonstrated a falling rate, with reduced drying time (from 960 to 540 min) as the convective temperature increased from 50 to 70°C. Moisture diffusivity increased with increasing hot air temperatures (4.15 ×10–10 – 1.03 ×10–9 m2/s), and the activation energy was determined as 41.82 kJ/mol. Slices dried at 70 °C exhibited higher color change than those dried at 50°C. The modified color model fitted the best color parameters, followed by the fraction model. Slices dried at 60°C showed lower hardness (34.73 N) and higher porosity (27.03 %) as compared with 50°C (49.33 N and 19.82 %) and 70°C (40.16 N and 21.90 %) temperature. Microstructure, moisture diffusion, and texture were closely linked to temperature and moisture content. Boiling and potassium metabisulfite significantly affected drying rate and texture of yam slices . MATLAB analysis provided detailed pore information for each hot air-dried sample, correlating with texture characteristics. This research offers substantial industrial significance by providing methods to enhance dried yam products' quality, shelf-life enhancement, and further exploration of starch extraction and recovery of valuable bioactive compounds.

Effect of novel blanching methods on Infra-red drying characteristics and quality attributes of elephant foot yam

The present study evaluated the effect of various pre-treatments (Potassium metabisulphite (KMS), KMS+Ultrasonication (KMSUS), KMS+Microwave (KMSMW), KMS+Hot water (KMSHWB) followed by infrared drying on the quality of Elephant Foot Yam (EFY). KMSMW-treated samples showed the fastest drying rate and highest moisture diffusivity, whereas the KMS-treated sample had the highest weight gain (171.57 %) in rehydration (80 °C). KMSMW and KMSHWB-treated samples exhibited softer textures in rehydration compared to control. Pre-treated samples had higher water absorption capacity and lower oil absorption capacity compared to the control. Pre-treatments also influenced the amylose content and the highest amylose content was observed for KMSUS (21.25 %). Pre-treatments positively influenced the retention of bioactive compounds and reduced the calcium oxalate (117.37 mg/g to 64.09 mg/g). Among all the pre-treatments, KMSHWB showed higher retention of bioactive compounds viz., TPC (297.67 mg GAE/100 g), TFC (922.22 mg QE/100 g), DPPH scavenging activity (57.91 %), ABTS (1.42 mmol TE/100 g) and lowest calcium oxalate (64.09 mg/100 g).

Determination of nutritional composition, enzyme inhibitory activity and antioxidant activity of pretreated, dehydrated <em style="mso-bidi-font-style: normal;">Amaranthus viridis</em> L. Leaves

Amaranthus viridis L., belongs to the family Amaranthaceae is a perennial edible plant, and traditionally used for medicinal treatments in South Asia. Despite the significant uses of the plant, availability of scientific data on plant's biological efficiency is lacking in the scientific domain. There is a higher potential and demand for dehydrated value-added products from the local and international market. Hence, the objective of the research was to determine the impact of pretreatments and dehydration on nutritional composition, phytochemical profile, antioxidant activity, and enzyme inhibitory activity of A.viridis leaves. Magnesium oxide 0.1% (w/v), sodium bicarbonate 0.1% (w/v) and potassium metabisulphite 0.5% (w/v) were selected as the best pretreatment based on the experiments. The pretreated leaves were steam blanched (5 min), followed by dehydration at 60 ± 1°C for 12 hours. Protein (21.90 ± 1.01%db), fat (3.70 ± 0.02%db), fiber (5.90 ± 0.05%db), ash (11.30 ± 0.12%db) and carbohydrate (49.24 ± 0.08%db) were determined. Data was statistically analyzed using one-way analysis of variance (ANOVA) test at a 95% confidence level (p < 0.05). A qualitative phytochemical analysis was conducted. The total phenolic content, 5.89 ± 0.30 mg in Gallic acid equivalents per 1g was determined in pretreated, dehydrated powder. FRAP, DPPH radical scavenging activity and ferrous ion chelating activity of the methanolic extract were 20.22 ± 0.45 mg Trolox equivalents, 1.68 ± 0.07 mg in Trolox equivalents and 3.83 ± 0.06 mg EDTA equivalents per 1g of pretreated dehydrated leaf powder, respectively. Methanolic extract (500 μg/mL) showed inhibitory activity of 25.30 ± 0.60% on 5-lipoxygenase, 30.80 ± 0.50% on alpha-amylase and 25.60 ± 0.40% on alpha-glucosidase. Inhibitory activity was not detected against lipase, acetylcholine esterase and butyrylcholinesterase enzymes. In conclusion, pretreated, dehydrated, A. viridis leaves are recommended as a health beneficial food ingredient.

Color, antioxidant and nutritional composition of dehydrated country bean (Lablab purpureus) seeds using solar drying techniques and pretreatments in Bangladesh

The country bean (Lablab purpureus), is a significant contributor of dietary protein and other essential components in human nutrition. Because of its elevated moisture content, it is susceptible to rapid decay, leading to losses after harvesting. The utilization of solar drying has attracted significant attention as a tactic to minimize nutrient depletion in dried goods and enhance their longevity. This study employed four solar drying techniques, namely long chimney, short chimney, box solar drying and open sun drying, along with pretreatments such as potassium metabisulfite, potassium-sodium tartrate, citric acid and ascorbic acid. The objective was to determine an effective solar drying method, combined with pretreatment, that can maintain the color and nutritional qualities of dried country bean seeds. The treatment combinations were organized in a factorial randomized complete block design (RCBD) with three replications. The data were subjected to a two-way analysis of variance (ANOVA) and a Duncan Multiple Range Test (DMRT) was conducted at a significance level of 5 % (p < 0.05). Results revealed that box solar dryer having the highest drying efficiency, retained the highest β-carotene (82.94 %), vitamin C (90.15 %), protein (96.48 %), fat (11.63 %), and ash (90.50 %) with maximum DPPH radical scavenging activity (lowest IC50 209.49 μg/ml) compared to other driers. Besides, country bean seeds have noteworthy proximate compositions, antioxidant activity, and bioactive components treated with 1 % potassium metabisulfite. Furthermore, the country bean seeds dehydrated in box solar dryer after 1 % potassium metabisulfite treatment received the highest acceptance score on the five-point Hedonic scale (4.83–4.89 out of 5.00) and color appearance and the similar trend was further supported by principal component analysis. Thus, it can be inferred that using a box solar dryer with a 1 % potassium metabisulfite pretreatment is a feasible method for preserving the color and nutritional value of country bean seeds and reducing postharvest losses.

Study on Clarification Effect and Stability of Fragrans Mead by Clarification Process

In order to study the best clarification conditions of osmanthus honey wine, single factor experiment and orthogonal experiment were used. The experimental results show that: When the type of clarifying agent was chitosan, the concentration of clarifying agent was 0.25%, and the clarifying time was 14 h, the maximum light transmittivity was 80.8±0.10%. After cold and hot treatment, standing at room temperature and oxidation stability test results showed that the stability of osmanthus honey wine with chitosan and potassium pyrosulfite was the best, and the wine body could not only maintain the flavor of the original wine, but also maintain the flavor of the original wine. The storage time is longer.After clarification, the sensory evaluation of the product was 86.9±0.69 points, the light transmittance was 80.8±0.10%, and the alcohol content was 6.4±0.05 %Vol.

Alkyl Radical Initiated Cyclization/Cascade for Synthesizing Lactam‐Substituted Alkyl Sulfones

Comprehensive SummaryAn alkyl radical initiated cyclization/tandem reaction of alkyl bromides and alkyl electrophiles by using potassium metabisulphite (K2S2O5) as a connector is developed for the synthesis of various lactam‐substituted alkyl sulfones. Notably, this process does not require a metal catalyst or metal powder reductant, highlighting its environmentally friendly features. The reaction demonstrates outstanding substrate adaptability and a high tolerance towards diverse functional groups. Furthermore, the biologically active molecules and commercially available drugs with a late‐stage modification are also highly compatible with this transformation. Mechanistic studies revealed that the reaction proceeds through a single‐step process involving intramolecular radical cyclization, "SO2" insertion, and external alkyl incorporation.

Hurdles Techniques (Combined Effects): A Novel Approach for Enhanced Broccoli Florets Stability, Quality, and Safety

This study demonstrates the changes in broccoli heads samples sensory, physicochemical, chemias blanching at 100 °C for 90 seconds, then dipping for 10 minutes in a coating solution concal, and microbial load after harvest. The samples were preserved using hurdles techniques such taining 0.15% potassium metabisulfite, 4% sodium chloride, 1% citric, 0.2% sodium benzoate and 1% chitosan. After coating samples were divided into two groups, one packaged using the aerobic method (A.P), and the other by vacuum method (V.P). Coated broccoli was stored at two conditions (ambient at 25 ± 3 °C and refrigeration at 4 ± 1 °C) for different period intervals. The control sample was blanched and packaged aerobically (uncoated). The combined treatments delayed the development loss of weight, titratable acid (TA), chlorophyll, and carotenoids, and prevented the growth of aerobic, anaerobic, psychrotrophic, coli form, mold, and yeast in the stored samples. Coated plus V.P. treatment demonstrated the highest weight, pigments, and TA values during storage. Further-more, it achieved the highest score in sensory evaluation after 50 and 240 days of both ambient and cold storage. Moreover, it inhibited the growth of tested microorganisms. So best treatment for the preservation of broccoli between 50 and 240 days of storage period was coated plus V.P. The combined technology application will lead to a safe product with optical shelf-life, improve microbial stability, and sensory quality. Thus, this technology is a technology that aims to improve the overall quality of food.

Drying Kinetics of Pear Slices in Greenhouse Solar Dryer

An experimental study was performed to determine the drying characteristics of pear using greenhouse based solar dryer and under open sun with natural convection. Prior to drying, sliced pear samples were pre-treated: i) control inside dryer i.e. with no dip, ii) blanching, iii) soaking in 2% KMS (Potassium Metabisulphite) solution, iv) blanching and soaking in 1% KMS solution, v) control outside dryer i.e. with no dip. The experimental drying data of pear were fitted to five different mathematical models viz. Exponential, Generalized exponential, Page’s, Logarithmic and Power law models, and drying rate constants and coefficient of models tested were determined by non-linear regression analysis. Among the various models tested to interpret the drying behaviour of pear, Page’s model was selected which gave best statistical indices of coefficient of determination (R2) and standard error of estimation (SEE) values.

Influence of Packaging Materials and Size on Shelf Life and Quality of White Button Mushroom during Storage

Background: Because of porous fruit body, high moisture content and extremely high respiration rate, the postharvest shelf life of button mushroom is a bottleneck in the mushroom industry as very high losses are recorded during transportation and marketing if the produce is not handled properly. Methods: NBS-5 strain of white button mushroom was treated with 0.05% potassium meta-bisulphite (KMS) followed by packing in 200, 400, 600, 800 and 1000 g capacity polyethylene (PE) and polypropylene (PP) bags of 150 gauge along with 0.01% vents. Dipping in water and packing in 200 g capacity bags was used as control. The packed mushrooms were stored at ambient (24-25°C and 58-62% RH) and low (4-6°C and 80-82% RH) temperature. Result: A significant increase in PLW (%) was recorded in all the treatments both at ambient and low temperature during storage but the increase was faster at room than refrigerated conditions. The white button mushroom in PE had a shelf-life of 7 and 16 days whereas it was 3 and 7 days, respectively, at ambient and low temperature storage conditions in control. A significant reduction in protein, sugars and phenols was recorded whereas polyphenol oxidase (PPO) increased notably during storage. Pack sizes of 200 and 400 g had an edge over 600, 800 and 1000 g with higher shelf-life at both storage conditions. PE packing was found comparatively better for extension of shelf-life compared to PP. The overall acceptability of button mushroom was also found better in 200 g and 400 g packing. The study revealed that the postharvest shelf-life of white button mushroom var. NBS-5 can be extended up to 16 days by packing in 200 and 400 g packs of PE stored at low temperature after pre-treatment of KMS.

Effect of Different Pretreatments and Air Temperatures on Drying Characteristics of Kachri (Cucumis callosus) Dried in Heat Pump Dryer

Kachri (Cucumis callosus) is an underutilized fruit of India widely found in the western part of Rajasthan during the rainy season. In this study kachri fruit slices were pretreated with different pretreatments such as hot water blanching, 0.1% w/v potassium metabisulfite (KMS) and 0.1% w/v magnesium oxide (MgO) at 800C for 3 min. Pretreated samples were dried in a heat pump dryer at 40, 50 and 600C and their drying characteristics such as moisture content, drying rate, moisture diffusivity and rehydration ratio were studied. The initial moisture content of control kachri was 893.04% (db) and for the pretreated sample, it was 906.75% (db) and the final moisture content was found 4 to 6% (db) for all the treatments. The KMS treated sample took less drying time and a higher drying rate followed by MgO, hot water blanching and control. Moisture diffusivity ranged from 1.90 × 10-07 to 8.28 × 10-07 m2/s as the temperature increased from 40 to 600C. The value of the rehydration ratio ranged from 2.1 to 5.03. It was found that both rehydration ratio and moisture diffusivity values increased with an increase in drying air temperature.

Colour, nutritional composition and antioxidant properties of dehydrated carrot (Daucus carota var. sativus) using solar drying techniques and pretreatments

Carrot is a seasonal perishable tuberous root vegetable which presents a preservation challenge owing to its elevated moisture content. Recently, carrot processing has received more attention because of its many health-promoting qualities and the reduction of postharvest losses in a cost-effective safe way. This study was designed to sort out the effective solar drying technique including pre-treatment that would retain the color and quality characteristics of dehydrated carrot. Carrot slices were subjected to dry using open sun drying (D1), solar drying long chimney (D2), solar drying short chimney (D3) and box solar drying (D4) techniques with the pretreatments of ascorbic acid 1 % (C3), citric acid 5 % (C4), potassium metabisulfite 1 % (C5) and potassium sodium tartrate 0.3 % (C6) before drying. Drying characteristics, nutritional attributes, phytochemicals and antioxidant of the dehydrated carrot samples were compared with the fresh sample and untreated (control) sample. Results showed that D4 was a good drying method to preserve nutritional quality with good appearance. Among the pretreatments, C5 and C4 resulted improved nutritional quality retention, enhanced visual acceptability and enriched antioxidant activities. PCA (Principal Component Analysis) and correlation matrix revealed that D4 with C5 retained the maximum amount of vitamin, minerals, total phenolic content, antioxidant and admirable dehydrated carrot color by inactivating enzymatic reaction. Therefore, box solar drying with potassium metabisulfite pretreatment would be very promising for functional carrot drying retaining acceptable color and nutrition composition.

Alkylsulfonylation of alkenes involving copper carbene coupling: access to alkyl–alkyl sulfones

A novel alkyl radical-initiated alkylsulfonylation of alkenes involving copper carbene coupling is developed for the synthesis of various alkyl–alkyl sulfones by employing potassium metabisulphite (K2S2O5) as a connector.

Controlling Enzymatic Browning in Apples: Inhibiting Polyphenol Oxidases Activity

Objective The browning phenomenon in fruits, particularly in apples, is a result of various enzymatic reactions, with polyphenol oxidases (PPOs) being the primary culprits. These enzymes catalyze the oxidation of phenolic compounds in the presence of oxygen, leading to the production of brown pigments, and compromising the quality, texture, and appearance of fruits. Aims This study aimed to investigate methods for mitigating enzymatic browning in apples by targeting the activity of PPO through the application of chemical treatments. Given the adverse impact of enzymatic browning on the sensory and nutritional qualities of apples, the research explored strategies involving chelating agents, antioxidants, agents of firmness, and acidifying agents. Methods Effective pre-treatment of apple samples was essential to overcome the natural cuticle barrier, thereby optimizing the efficacy of subsequent chemical interventions. The research revolved around the application of chelating agents, antioxidants, agents of firmness, and acidifying agents to suppress PPO activity. The systematic evaluation considered various concentrations of ascorbic acid, potassium metabisulfite (KMS), and sodium benzoate under diverse temperature and potential hydrogen (pH) conditions. Results The findings underscored the effectiveness of a variety of chemical treatments in inhibiting PPO activity, resulting in a noteworthy reduction in enzymatic browning in apples. Ascorbic acid exhibited substantial PPO inhibition at specific concentrations, while KMS and sodium benzoate demonstrated varying degrees of inhibition, ranging from moderate to prominent. Notably, the combination of KMS and sodium benzoate at an optimal concentration emerged as a highly effective approach, effectively preventing enzymatic browning across diverse conditions. Conclusion In conclusion, this research emphasizes the efficacy of chemical treatments, encompassing chelating agents, antioxidants, agents of firmness, and acidifying agents, in mitigating PPO activity and controlling enzymatic browning in apples. The synergistic effect of potassium metabisulfite and sodium benzoate displays significant promise, offering a viable solution to extend the shelf life of apples while preserving their sensory and nutritional attributes. These findings hold substantial significance in the realm of food preservation, with the potential to contribute to addressing global food scarcity challenges.

Effect of Different Concentrations of Potassium Metabisulphite and Bavistin on Postharvest Life of Litchi (Litchi chinensis Sonn var. Muzaffarpur)

Litchi (Litchi chinensis Sonn var. Muzaffarpur) is cultivated in 57 districts of Nepal. However, proper post-harvest loss reduction activities are lacking, resulting in significant losses every year. In June 2023, an experiment on Litchi post-harvest was conducted at HRS, Malepatan. The Litchi fruits were uniformly mature and treated with varying concentrations of potassium metabisulfite (50, 75, 100, and 125 ppm) and Bavistin at 100 ppm. They were then stored at ambient conditions (29±4°C and RH 75±5%) for 10 days. The following parameters were recorded: physiological loss in weight (PLW), decay loss, total soluble solids (TSS), titratable acidity (TA), ascorbic acid content (Vit-C), and fruit weight to juice ratio. The fruit that was treated with 50 ppm of potassium metabisulphite recorded the lowest PLW at 20.12%. The fruit treated with 125 ppm of potassium metabisulphite had a minimum decay loss of 23.08%. The control treatment had the highest TSS at 23.65% with a minimum TA of 0.50%. The fruit treated with 100 and 125 ppm of potassium metabisulphite had the maximum ascorbic acid content at 87 mg and 85 mg, respectively, and the highest fruit weight-to-juice ratio at -2.80 and 2.73, respectively. Therefore, this study concludes that applying potassium metabisulfite at a concentration of 100-125 ppm is suitable for postharvest treatment of Litchi fruit to prolong its shelf life and maintain its quality parameters.

Cyto/genotoxicity of potassium metabisulfite and antimutagenic effect of piperine

Potassium metabisulfite is a white crystalline powder used in wine production and food preservation. Piperine is an alkaloid of the piperidine series and it is the main ingredient of black pepper. The aim of the present study was to evaluate the cyto/genotoxic effects of potassium metabisulfite and antimutagenic effect of piperine using the Allium test. To test the cyto/genotoxicity of potassium metabisulfite, three concentrations were used: 0.5, 1.0 and 2.0 g/L. To evaluate the antimutagenic effect of piperine, the following concentrations were applied: 3.3, 6.6 and 13.3 µL/mL. Our results demonstrated that all three tested concentrations of potassium metabisulfite significantly reduced root growth. Mitotic index values significantly decreased after the treatment with all three concentrations of potassium metabisulfite. An increased frequency of apoptotic cells was observed for the two highest concentrations of potassium metabisulfite, while a statistically different frequency of necrosis was detected for all three potassium metabisulfite concentrations in comparison with control. The total number of cytotoxic markers differed between all three potassium metabisulfite concentrations and control. A significantly higher frequency of sticky chromosomes for the two highest potassium metabisulfite concentrations, as well as an increased number of chromosomal bridges for median potassium metabisulfite concentration as compared to control group was determined. A significantly higher number of binuclear cells was detected for the highest potassium metabisulfite concentration. A significant difference between the two highest potassium metabisulfite concentrations and control was established for the total number of aberrant cells. As for the results for piperine, a reduction in the roots' growth was observed between the two highest piperine concentrations and negative control. The mitotic index decreased after treatment with all three piperine concentrations in comparison with negative and positive control. A significant difference in the frequency of apoptosis between median piperine concentration and positive control was detected. An increased frequency of necrosis between the two highest piperine concentrations and both controls was determined. The total number of cytotoxicity markers increased between the highest piperine concentration and both controls. A significantly higher frequency of chromosomal bridges between the two highest piperine concentrations and negative control was observed. The total number of aberrant cells differed between two highest piperine concentrations and negative control. This study demonstrated that potassium metabisulfite manifests antiproliferative, cytotoxic and genotoxic effects. Similarly, antiproliferative properties of piperine have been observed, while its antimutagenic potential has not been demonstrated. Further studies are needed to strengthen these observations.