Integrated drying model of lychee as a function of temperature and relative humidity.

Drying is a universal method applied for food preservation. To date, several models have been developed to evaluate drying kinetics. In this study, lychee was dried employing a hot air dryer, and the drying kinetics was evaluated by comparing the Newtonian model, Henderson and Pabis model, Page model, and Logarithmic model. However, temperature and relative humidity, the key driving forces for drying kinetics, are not considered by these models. Thus, an integrated drying model, as a function of temperature and relative humidity, was developed to predict the hot air-drying kinetics and mass transfer phenomena of lychee followed by the calibration and validation of the model with independent experimental datasets. The model validation consisted of Nash- Sutcliffe model coefficient (E), coefficient of determination (R2) and index of agreement (d) and all of them were found close to 1 indicating perfect model fit. Besides, the developed model was applied for process optimization and scenario analysis. The drying rate constant was found as a function of temperature and relative humidity that was high at high temperature and low relative humidity. Interestingly, temperature showed a higher effect on the drying rate constant compared to relative humidity. Overall, the present study will open a new window to developing further drying model of lychee to optimize quality its quality parameters.

Effect of cooking methods on the nutritional quality of selected vegetables at Sylhet City.

The study was carried out to analyze the impacts of boiling, steaming, and microwave cooking on the physicochemical properties, the content of bioactive compounds, and boiling effect on mineral and heavy metal content of six widely consumed vegetables in Bangladesh's north-eastern region. In comparison to raw, boiled, and microwave-cooked vegetables, those that are steam-cooked retain a higher percentage of ß-carotene with the exception of carrots. Boiling vegetables led to the most substantial reduction in ascorbic acid content (from 9.83 % to 70.88 %), with spinach experiencing the greatest decline. In contrast, microwaving had the mildest effect on ascorbic acid, preserving over 90 % of the initial content. The decrease in carotene content may be associated with color changes (decreasing greenness and increasing hue angle) in the chosen vegetables. The colorimeter shows the L* value (lightness/darkness) of all cooked vegetables significantly decreased. In terms of total polyphenol content (TPC) and total flavonoid content (TFC), boiling had a higher negative effect on most vegetables than the other two cooking methods, with losses of up to 70.3 % and 82.27 %, respectively. All cooked vegetables, with the exception of carrot and microwave pumpkin, had substantial reductions in free radicals scavenging activity, with losses ranging from 8.48 % to 56.73 %. In comparison to raw vegetables, boiled vegetables significantly lost minerals like potassium (K), magnesium (Mg), zinc (Zn), copper (Cu), and manganese (Mn). On the other hand, the calcium (Ca) and iron (Fe) content of all cooked vegetables, except for carrots and peas, exhibited an increase, ranging from 6 to 17 % and 6-12 %, respectively. The Cr concentration in all vegetables and the Zn, Fe, Mn, and Cd content in the spinach sample was higher than the FAO/WHO recommended maximum permissible level (MPL), whereas the accumulation of Cu and Ni content was lower in all vegetables. In conclusion, this study demonstrated that microwaving was the most effective method for retaining the nutritional value of vegetables, while steaming had a moderate impact.

Characteristics of the Beef Cheek Meat-Based Sausage Added with Snakehead (Channa striata) Gelatin.

This study is aimed at determining the functional effect of snakehead fish gelatin as a binder on the characteristics and shelf life of beef cheek-based emulsion sausage compared with bovine commercial gelatin. The level of snakehead fish gelatin used was 0%, 1%, 2%, and 3%, while that of bovine commercial gelatin was 2% with a storage time of 0 to 28 days in the refrigerator (4 ± 2°C). Emulsion stability, cooking loss, proximate composition, texture profile, and microstructure of sausage were initially determined before storage; then, observations were made every seven days to determine the shelf life of sausages based on pH, antioxidant activity, and TBA reactivity. Characteristics such as emulsion stability, proximate composition, and texture profile were influenced by the treatment (p < 0.05). The gelatin level significantly affected the water holding capacity of sausages (p < 0.05), but the storage time did not (p > 0.05). On the other hand, the pH, TBA reactivity, and antioxidant activity of sausages were not only affected by gelatin level (p < 0.05) but also by storage time (p < 0.05). The sausage microstructure confirms the use of 2% snakehead fish gelatin to make sausages with properties similar to 2% commercial bovine gelatin. The byproduct of the snakehead fish industry can be used as a gelatin alternative to produce sausages. This gelatin has the potential as a binder, which can functionally improve sausage characteristics. This effectiveness can boost the water holding capacity of sausages, although it has not been effective in inhibiting fat oxidation which causes an increase in malonaldehyde levels.

Impact of superheated steam roasting on changes in antioxidant and microstructure properties of raw and processed cocoa cotyledon.

This research focused on the roasting of cocoa beans at 184 °C for 16 min duration in a superheated steam oven using two separate modes of heating: convection mode and superheated steam mode. After roasting, the antioxidant properties of the cooked cocoa were assessed as ferric reducing antioxidant power activity (FRAP), DPPH radical scavenging activity, total flavonoid content (TFC) and total phenol content (TPC). The micro structural properties of raw and processed cocoa beans were observed using scanning electron microscopy (SEM). As discovered in the scan, conventional roasting showed a nearly complete rapture of the cytoplasmic network system and the destruction of the organelles, whereas superheated steam mode showed satisfactory images. Studies indicated that superheated steam roasting preserved significantly (p < 0.05) greater antioxidant properties as opposed to conventional method of roasting.

Effect of Thermal Processing on Physicochemical and Antioxidant Properties of Raw and Cooked Moringa oleifera Lam. Pods.

Moringa is regarded as a miracle tree because all components of the plant, including the roots, leaves, pod, and flowers, have significant nutritional and therapeutic value. Moringa oleifera Lam. pods have excellent antioxidant characteristics and are a good source of protein, carbohydrate, fat, vitamins, beta-carotene, amino acids, and phenolic compounds. The pods of Moringa oleifera Lam. were collected from the local market of Sunamganj, and their nutritional value was assessed in raw condition and after thermal processing. The goal of this research was to observe how the thermal temperature affected the antioxidant and physicochemical qualities of thermally-processed Moringa oleifera Lam. pods. Thermal treatment diminished the amount of crude protein, fat, carbohydrate, ash, ascorbic acid, and beta-carotene in the pods, as well as DPPH, total phenol content, and total flavonoid content. The moisture percentage of raw and thermally-processed Moringa oleifera Lam. pods was determined to be 83.12%, 86.03% with a total ash level of 2.01%, and 1.8%, respectively. The crude protein, fat content, and carbohydrate were 3.0%, 0.1%, and 3.2%, respectively, in thermally-processed pods. The values for total phenol content, total flavonoid content, vitamin C, DPPH free radical scavenging activity, and ß-carotene were 28.13 mg, 2.98 mg, 38.23%, 3.98 mg, and 0.12 mg, respectively, in raw samples whereas 24.56 mg, 2.72 mg, 3.50 mg, 34.32%, and 0.0904 mg, respectively, in thermally-processed samples. According to the findings, Moringa oleifera Lam. pods have high nutritional content and thus can be used as an excellent source of diet, and even after thermal processing, a significant nutritive value remains in the Moringa oleifera Lam. pods.

Tea Polyphenols and Their Preventive Measures against Cancer: Current Trends and Directions.

Cancer is exerting an immense strain on the population and health systems all over the world. Green tea because of its higher simple catechin content (up to 30% on dry weight basis) is greatly popular as an anti-cancer agent which is found to reduce the risks of cancer as well as a range of other diseases. In addition, several in vitro and in vivo studies have shown that green tea possesses copious health benefits like anti-diabetic, anti-obese, anti-inflammatory, neuro-protective, cardio-protective, etc. This review highlights the anti-carcinogenic effects of green tea catechins integrating the recent information to gain a clear concept. Special emphasis was given to the effectiveness of green tea polyphenols (GTP) in the prevention of cancer. Overall, green tea has been found to be effective to reduce the risks of breast cancer, ovarian cancer, liver cancer, colorectal cancer, skin cancer, prostate cancer, oral cancer, etc. However, sufficient information was not found to support that green tea consumption reduces the risk of lung cancer, esophageal cancer, or stomach cancer. The exciting data integrated into this article will increase interest in future researchers to garner more fruitful information on the relevant topics.

Nitrites in Cured Meats, Health Risk Issues, Alternatives to Nitrites: A Review.

Nitrite is one of the most widely used curing ingredients in meat industries. Nitrites have numerous useful applications in cured meats and a vital component in giving cured meats their unique characteristics, such as their pink color and savory flavor. Nitrites are used to suppress the oxidation of lipid and protein in meat products and to limit the growth of pathogenic microorganisms such as Clostridium botulinum. Synthetic nitrite is frequently utilized for curing due to its low expenses and easier applications to meat. However, it is linked to the production of nitrosamines, which has raised several health concerns among consumers regarding its usage in meat products. Consumer desire for healthier meat products prepared with natural nitrite sources has increased due to a rising awareness regarding the application of synthetic nitrites. However, it is important to understand the various activities of nitrite in meat curing for developing novel substitutes of nitrites. This review emphasizes on the effects of nitrite usage in meat and highlights the role of nitrite in the production of carcinogenic nitrosamines as well as possible nitrite substitutes from natural resources explored also.

Antimicrobial activity of peels and physicochemical properties of juice prepared from indigenous citrus fruits of Sylhet region, Bangladesh.

Scientists are indeed fascinated by the pharmacologically important chemicals found in medicinal plants. Citrus fruits possess several curing agents for the prevention of diseases. Therefore, experiments were carried out to test the antibacterial activity of methanolic extracts of peels from various locally available citrus fruits such as citron (Citrus medica), satkora (Citrus macroptera) and adajamir (Citrus assamensis) against Bacillus spp. and E. coli using the disc diffusion method. Different physicochemical characteristics of fruit juice were also determined. Methanolic extract of satkora peel had the highest antibacterial activity of 2.2 and 2.6 cm while adajamir had the lowest antibacterial activity of 1.7 and 2.1 cm as ZOI against Bacillus spp. and E. coli, respectively. In the case of pH and total soluble solids (TSS), the three citrus varieties showed a small variation where satkora showed the highest total phenolic content (TPC), vitamin C content, and antioxidant activity than the others. Citrus fruits can be exploited as antibacterial and antioxidant ingredients in food and nutraceuticals, according to the findings of this study.

A Comprehensive Review on Bio-Preservation of Bread: An Approach to Adopt Wholesome Strategies.

Bread is a food that is commonly recognized as a very convenient type of food, but it is also easily prone to microbial attack. As a result of bread spoilage, a significant economic loss occurs to both consumers and producers. For years, the bakery industry has sought to identify treatments that make bread safe and with an extended shelf-life to address this economic and safety concern, including replacing harmful chemical preservatives. New frontiers, on the other hand, have recently been explored. Alternative methods of bread preservation, such as microbial fermentation, utilization of plant and animal derivatives, nanofibers, and other innovative technologies, have yielded promising results. This review summarizes numerous research findings regarding the bio-preservation of bread and suggests potential applications of these techniques. Among these techniques, microbial fermentation using lactic acid bacteria strains and yeast has drawn significant interest nowadays because of their outstanding antifungal activity and shelf-life extending capacity. For example, bread slices with Lactobacillus plantarum LB1 and Lactobacillus rossiae LB5 inhibited fungal development for up to 21 days with the lowest contamination score. Moreover, various essential oils and plant extracts, such as lemongrass oil and garlic extracts, demonstrated promising results in reducing fungal growth on bread and other bakery products. In addition, different emerging bio-preservation strategies such as the utilization of whey, nanofibers, active packaging, and modified atmospheric packaging have gained considerable interest in recent days.

Response Surface Approach to Optimize the Conditions of Foam Mat Drying of Plum in relation to the Physical-Chemical and Antioxidant Properties of Plum Powder.

This research was done to optimize the influence of various egg albumin (EA) concentrations of 2, 4, and 6% as a foaming agent and whipping times of 5, 10, and 15 minutes, on physicochemical and antioxidant properties of plum powder produced using response surface methodology (RSM). Physical properties of the foam such as density, porosity, and expansion were determined. After drying and powder manufacturing, physical properties, namely, the water absorption index (WAI) and water solubility index (WSI), as well as chemical characteristics such as pH, titratable acidity, and browning index, were assessed. Finally, antioxidant capabilities such as the total phenol content (TPC), DPPH scavenging activity, beta carotene, and total flavonoid content (TFC) were measured. According to the findings, both whipping duration and EA concentration had a substantial effect on the foam forming characteristics. Foam expansion increased significantly with EA concentration and whipping time increase, but foam density exhibited an inverse relationship as expected. Increases in EA concentration and whipping duration both raised pH values whereas titratable acidity exhibited an inverse tendency as variable quantity rose. The browning index dropped as EA concentration increased. Antioxidant qualities were retained in dried sample powder as compared with the fresh sample, and they were also altered by variable changes. Overall, a 4% EA concentration for 10 to 15 minutes produced the best dehydration effects with the most antioxidant retention.

Optimization of substrate composition for pectinase production from Satkara (Citrus macroptera) peel using Aspergillus niger-ATCC 1640 in solid-state fermentation.

Pectinase is an enzyme having a broad industrial and commercial application. However, higher production costs may be the major constraint for the wide-scale application of pectinase. Therefore, researchers are trying to reduce the pectinase production cost for subsequent application in the industrial processes by using a unique substrate and optimizing the fermentation medium components and process conditions. The main purpose of the current study was to optimize medium composition for pectinase production using Aspergillus niger-ATCC 1640 in the solid-state fermentation. The Response Surface Methodology (RSM) was performed to evaluate the effects of variables, specifically the concentrations of Satkara peel, urea, (NH4)2PO4, NH4NO3, KH2PO4, ZnSO4, and MgSO4.7H2O on pectinase production in the solid substrate. Firstly, a two-factorial design, Plackett-Burman design (PBD) was applied to screen the variables that significantly influenced the pectinase production. After finding the critical variables, 15 experimental runs were carried out using a Box-Behnken design (BBD) to derive a statistical model for optimizing the concentrations of the selected variables. The PBD model revealed that Satkara peel, urea, and (NH4)2SO4 significantly affected the pectinase production. RSM results indicated that the predicted response for pectinase production was in good agreement with experimental data (R2 = 0.9836). Under the optimized condition of Satkara peel (8.4 g/L), urea (0.5 g/L), and (NH4)2SO4 (2.7 g/L), the pectinase activity was predicted to be 0.6178 µmol/mL. In the present study, the experimental pectinase production achieved 0.6045 µmol/mL. The study revealed that optimization through RSM could improve the pectinase production from Satkara peel.

Application of immersion pre-treatments and drying temperatures to improve the comprehensive quality of pineapple (Ananas comosus) slices.

Drying of pineapple slices combined with different pre-treatments was done to reduce various adverse changes by adding satisfactory value. Process optimization was done by dipping the pineapple slices in four different solutions (1% trehalose, 2% NaCl, 10% sucrose, and 10% fructose) before drying. The effects of different pre-treatments and drying temperatures of 50, 55, and 60 °C with a constant 30% relative humidity (RH) were optimized based on the quality attributes, drying time and microbial load of dried pineapple slices. The optimal drying temperature was 55 °C using 1% trehalose pre-treatments based on the physical and biochemical properties. The reconstituted dried pineapples implied at this condition, contributed to the better structure preservation as indicated by the lower shrinkage (0.21) and the higher Coefficient of Rehydration (0.941), and rehydration ratio (6.840). On the other hand, the retention of color, vitamin C, B vitamins, and antioxidant activity of the samples were decreased by increasing drying time and temperatures. The highest Total Phenolic Content (121.02 mg GAE/100g), Total Flavonoid Content (8.72 mg QE/100g), and DPPH radical scavenging activity (7.22 EC50 g/100g) were found at 60 °C drying temperature with 10% fructose pretreatment's samples. The lowest drying time required was 7.64 h using 2% NaCl pre-treatment at 60 °C, considering the time required to reach 20% moisture content in the dried product at 30% RH. Based on the reported results, it is concluded that 1% trehalose at 50 °C can be used to develop high quality pineapple snacks, which maintained the maximum desired physicochemical and nutritious properties. This study could play an essential role in meeting the emerging demand of developing good quality nutritious dried pineapple snacks.

Effects of Incorporation of Jackfruit Rind Powder on Chemical and Functional Properties of Bread.

Nowadays, there is a rising interest towards consuming health beneficial food products. Bread-as one of the most popular food products-could be improved to 'healthy bread' by addition of ingredients high in protein, dietary fiber and low in calorie. Incorporating Jackfruit rind powder (JRP) as a by-product rich in dietary fiber in bread, could not only provide health beneficial bread products, but also lead to develop an environmental friendly technology by solving the problem of waste disposal of residues. In this study, addition of jackfruit rind powder (JRP) as a high dietary fiber and functional ingredient in bread was examined. The results showed that incorporation of JRP in bread improved functional properties of flour such as Oil Holding Capacity (OHC), Water Holding Capacity (WHC) and pasting properties. Addition of 5%, 10% and 15% of JRP in wheat flour caused significantly (p < 0.05) higher insoluble, soluble and total dietary fiber in flour and bread products. Results from proximate composition indicated that all breads substituted with JRP, contained significantly (p < 0.05) higher fiber, moisture and fat. Obtained results confirmed that the JRP has great potential in development of functional foods especially functional bread products.

Influences of superheated steam roasting on changes in sugar, amino acid and flavour active components of cocoa bean (Theobroma cacao).

BACKGROUND: Roasting is one of the important unit operations in the cocoa-based industries in order to develop unique flavour in products. Cocoa beans were subjected to roasting at different temperatures and times using superheated steam. The influence of roasting temperature (150-250°C) and time (10-50 min) on sugars, free amino acids and volatile flavouring compounds were investigated. RESULTS: The concentration of total reducing sugars was reduced by up to 64.61, 77.22 and 82.52% with increased roasting temperature at 150, 200 and 250°C for 50 min, respectively. The hydrophobic amino acids were reduced up to 29.21, 36.41 and 48.87% with increased roasting temperature at 150, 200 and 250°C for 50 min, respectively. A number of pyrazines, esters, aldehydes, alcohols, ketones, carboxyl acids and hydrocarbons were detected in all the samples at different concentration range. Formation of the most flavour active compounds, pyrazines, were the highest concentration (2.96 mg kg-1 ) at 200°C for 10 min. CONCLUSION: The superheated steam roasting method achieves the optimum roasting condition within a short duration Therefore, the quality of cocoa beans can be improved using superheated steam during the roasting process. © 2017 Society of Chemical Industry.

Biochemical and radical-scavenging properties of sea cucumber (Stichopus vastus) collagen hydrolysates.

The molecular mass distribution, amino acid composition and radical-scavenging activity of collagen hydrolysates prepared from collagen isolated from the sea cucumber Stichopus vastus were investigated. ß and α1 chains of the collagen were successfully hydrolysed by trypsin. The molecular mass distribution of the hydrolysates ranged from 5 to 25 kDa, and they were rich in glycine, alanine, glutamate, proline and hydroxyproline residues. The hydrolysates exhibited excellent radical-scavenging activity. These results indicate that collagen hydrolysates from S. vastus can be used as a functional ingredient in food and nutraceutical products.