Prevention of browning reaction in banana jam during storage by physical and chemical treatments

Bananas are fruits that quickly turn brown after being peeled or cooked. The browning reaction reduces the quality of the appearance and shelf life of banana jam. Therefore, this study was aimed to evaluate the effect of chemical blanching and anti-browning agents on reducing browning reactions and maintaining the quality of banana jam during storage. In this study, Musa paradisiaca cv. Nipah was used to produce banana jam. The banana jam was prepared using three different treatments. The first treatment was prepared without hot water blanching treatment and with the addition of ascorbic acid and sodium metabisulphite. The jam was prepared with banana pulp, sugar, citric acid, and pectin. This treatment act as a control. The banana jam for the second and third treatments was prepared using the same ingredients as treatment one. In the second treatment, the sliced banana was blanched in hot water (80°C) for 10 mins, whereas in treatment three, the banana slices were dipped into 1.5% of ascorbic acid solution at 80°C for 10 mins. During the cooking process, 0.1% of sodium metabisulphite was added into the jam, for treatments two and three. The jam was cooked until the temperature reached 105°C and the total soluble solids range from 68 - 70°Bx. The banana jam was filled in glass jars, sterilized in a hot water bath at 80°C for 10 mins, cooled to 27°C (room temperature) before being stored at room temperature. The analysis observed were pH, total soluble solids, titrable acidity, colour, browning index, and textural properties. The samples were stored at room temperature for 60 days. The observations were made every 15 days for two months. After 60 days of storage, all treatments showed positive changes and a significant difference (p<0.05) in physicochemical and texture analyses. Overall, hot water blanching and chemical treatments significantly reduced the browning reaction in the banana jam. Therefore, treatment three had the best ability to slow down the browning reaction and deterioration rate of banana jam during room temperature storage.

Control of browning during seed germination of Meizotropis pellita: a rare and an endangered plant

Meizotropis pellita is a rare, endangered and threatened plant species found in Patwadanger forest. In nature this species grows from rootstock in precise and sensitive habitats. However, phenolic compounds provoke browning reaction which is responsible for lethal browning in plant tissue culture and hindering in vitro germination. The aim of this study was to minimize the effect of phenolic compound during seed germination. We evaluate different antibrowning treatments in Meizotropis pellita seeds. The seeds were pretreated in Polyvinylpyrrolidone and then treated seeds were cultured on MS media and sterilized seeds were directly inoculated on PVP containing MS media. These culture media incubate under dark and light conditions at different durations respectively. Our results showed that addition of antibrowning agent, PVP inhibit onset of browning. Dark and light condition also played a crucial role on onset of browning. Delayed and low intensity of browning were observed in case of seeds that were inoculated on MS media containing PVP and were kept in dark. The present research offers a positive in vitro seed germination protocol for Meizotropis pellita conservation.

Variation in the Physical and Functional Properties of Yam (Dioscorea spp.) Flour Produced by Different Processing Techniques

Research on the processing of yam (Dioscorea spp.) into flour is aimed at optimizing techniques to obtain a material with high physicochemical and functional properties. The present study investigates the effect of the processing techniques on the levels of inulin, organic acids, total phenolics (TP), antioxidant capacity, and polyphenol oxidase (PPO) and peroxidase (POD) activities, as well as on the physicochemical properties of flour derived from two yam species—Dioscorea esculenta and Dioscorea bulbifera. All tubers were peeled and sliced, then subjected to different processing techniques through blanching, soaking, and drying. The results revealed that freeze-drying appears to be the best technique in achieving the highest whiteness index of yam flour. This coincided well with the low phenolics content and POD activity, which suggests a reduced enzymatic browning reaction in the freeze-dried yam flour. On the other hand, chemical analyses showed that D. esculenta and D. bulbifera flours have the highest levels of inulin (23.0 and 27.8 g/100 g DW, respectively) and succinic acid (7.96 and 7.65 g/100 g DW, respectively) in the samples subjected to direct oven-drying. Oven drying without pretreatment neither blanching nor water steeping maintained antioxidant activity in the flour derived from both D. esculenta and D. bulbifera.

Physics-Based Digital Twin Identifies Trade-Offs Between Drying Time, Fruit Quality, and Energy Use for Solar Drying

Solar drying is regarded as a less reliable process compared to continuous hot-air drying due to the intermittency of solar radiation. This problem is mitigated by equipping solar dryers with thermal storage, dehumidifier units, or auxiliary heating that enhances drying continuity during night time. In this study, we combine a mechanistic fruit drying model, quality models (vitamin C decay and browning reaction) and weather data to evaluate the drying characteristics and quality evolution of apple fruit with and without the aforementioned improvement strategies. By coupling to measured weather conditions, a digital twin of the drying fruit is established. The twin outputs drying times and final product quality for a specific fruit type and size, a particular dryer configuration, and specific weather conditions. The trade-offs between drying time, final product quality and energy use for the different improvement strategies of solar drying are documented. We found that solar drying may benefit from the slower drying due to the improvement of product quality. Compared to the other improvement strategies, dehumidification of the drying air is shown to be superior in retaining the vitamin C content and prohibiting the browning reaction. However, in general, drying with auxiliary heating is found to balance the trade-offs between drying time, final product quality and energy use since the weather-dependency of the process is mitigated. Additionally, we quantified the impact of a pre-treatment process that modifies the permeability of the fruit tissue by breaking the cell membrane. We found that inducing such lysis is more effective in decreasing the drying time when drying is conducted at low (room) temperature. This study shows that using the developed digital twin, future drying process and control strategies could be optimized in real-time for every single drying run.

Convective Baking Characteristics and Effective Moisture Diffusivities of Yellow Mealworms

Yellow mealworm is an alternative protein source studied by researchers to provide an alternative supply of protein to meet the growing demands of human consumption. In this research, convective baking of yellow mealworms at 80°C, 100°C, and 120°C was carried out to study the baking kinetics and product quality. Studies showed the typical falling trend of the moisture ratio curves, which are typical for most bioproducts that undergo hot air treatment. Mathematical modelling showed that the Page model gave a good prediction on the baking kinetics with high fitting accuracy (R2>0.99). Effective diffusivities were determined from 1.66 x 10-11 to 2.88 x 10-11 m2/s within the temperatures tested. The activation energy was estimated at 15.7 kJ/mol based on the Arrhenius equation. The final baked samples appeared darker in color because the browning reaction and reduction in bulk density and product length were observed in the range of 48-54% and 3.0-16.3%, respectively.

Rate of physical appearance changes on yellowness in salak during preservation in room storage

Background: Discoloration was one indicator of food damage including in fruits, since the change may be used as a quality measurement. Salak became one of the commodities that often experience the browning reaction that may change the color. Since the yellow was close to the consumer preference along the preservation in salak, this color should be notified and may be represented as polyphenol change. Objectives: The focus of this study was to determine the pattern of inhibition of browning reactions in salak using HIO.Methods: This research determined the color level of yellow using digital color meter of salak that was stored in room temperature in aseptic treatment for 12 days. Result: Discoloration appeared in salak and it was clearly determined the change since a week of storage. The rate of discoloration was able to be detected highly after one week of storage. Conclusion: The discoloration of yellow color and the rate of salak could be detected specifically based on the day of storage. This research may open the information for the consumer to predict the storage time of salak based on the appearance of yellow color.

The effects of reaction parameters on the non-enzymatic browning reaction between l-ascorbic acid and glycine

The non-enzymatic browning (NEB) reaction between l-ascorbic acid (ASA) and glycine (Gly), including the effects of temperature (110–150 °C), time (10–150 min) and pH (4.5, 6.8, 8.0 and 9.5) on the formation of un-colored intermediate products (UIPs), browning products (BPs) and volatile products (VPs), were investigated. The results showed that pH had a remarkable effect on the reaction. The characteristics of zero-order kinetics for the formation of UIPs and BPs were discussed, and the corresponding activation energy (Ea) was also calculated. When the pH was 4.5, the Ea for the formation of UIPs was approximate 53.76 kJ/mol and less than that at other pH values; while the Ea for BPs formation was approximate 94.06 kJ/mol and much higher than that at other pH values. The results suggested that an acidic environment facilitated the generation of UIPs, but did not remarkably promote the formation of BPs. The possible reaction pathway between ASA and Gly was proposed according to the experimental results.

EFFECTS OF GROUNDNUT (ARACHIS HYPOGEA L) VARIETIES ON THE FLAVOUR PROFILE AND CONSUMER ACCEPTABILITY OF DAKUWA (A CEREAL-GROUNDNUT BASED SNACK)

The quality of Dakuwa can be affected by raw materials and processing methods. This work studied the effects of groundnut (Arachis hypogea L.) varieties (Campala, white and Sere) on the colour, flavour profile and sensory properties of Dakuwa. The flavour profile of the Dakuwa samples was analysed with gas chromatography – mass spectroscopy (GC – MS), colour by chroma meter and proximate composition using standard methods while sensory evaluation was done by 25 untrained panelists. The results were analysed using one way analysis of variance. Dakuwa sample with Campala groundnut (DKWC) had the highest concentration of alcohols (20 μg /100 g), aldehydes (86 μg /100 g), ketones (1.9 μg /100 g), heterocyclic aromatic compounds (11.2 μg /100 g), and total flavour compounds (151 μg /100 g) suggesting higher lipid oxidation and Maillard reaction compared to Dakuwa with Sere and White groundnuts. DKWC had significantly lower L* (lightness) value and significantly higher browning index (84.75) suggesting a higher browning reaction compared to other samples. Sensory evaluation results indicated no significant (p > 0.05) difference in the samples. It can be concluded that any of the three groundnut varieties can be used to produce Dakuwa without altering its sensory qualities.

Antioxidant Compounds for the Inhibition of Enzymatic Browning by Polyphenol Oxidases in the Fruiting Body Extract of the Edible Mushroom Hericium erinaceus

Mushrooms are attractive resources for novel enzymes and bioactive compounds. Nevertheless, mushrooms spontaneously form brown pigments during food processing as well as extraction procedures for functional compounds. In this study, the dark browning pigment in the extract derived from the edible mushroom Hericium erinaceus was determined to be caused by the oxidation of endogenous polyphenol compounds by the polyphenol oxidase (PPO) enzyme family. These oxidized pigment compounds were measured quantitatively using a fluorospectrophotometer and, through chelation deactivation and heat inactivation, were confirmed to be enzymatic browning products of reactions by a metalloprotein tyrosinase in the PPO family. Furthermore, a transcript analysis of the identified putative PPO-coding genes in the different growth phases showed that tyrosinase and laccase isoenzymes were highly expressed in the mushroom fruiting body, and these could be potential PPOs involved in the enzymatic browning reaction. A metabolite profiling analysis of two different growth phases also revealed a number of potential enzymatic browning substances that were grouped into amino acids and their derivatives, phenolic compounds, and purine and pyrimidine nucleobases. In addition, these analyses also demonstrated that the mushroom contained a relatively high amount of natural antioxidant compounds that can effectively decrease the browning reaction via PPO-inhibitory mechanisms that inhibit tyrosinase and scavenge free radicals in the fruiting body. Altogether, these results contribute to an understanding of the metabolites and PPO enzymes responsible for the enzymatic browning reaction of H. erinaceus.