Chemical Treatment of Black Tiger nut Tubers (Cyperusesculentus) Variety to Obtain a Bio-based Product

The purpose of this study is to improve microbiological qualities of black tiger nut tubers. Thereby, black variety of tiger nut tubers (Cyperus esculentus) were differently processed in ascorbic acid and alkaline (Ca(OH)2 and Kanwa (alkaline calcium carbonate locally used to soften vegetable)) solutions at different concentrations and temperatures. The effect of these treatments on the water content (swelling), soluble loss, dehulling efficiency and microbial load was investigated. Water content or swelling of the tiger nut soaked in acid and alkaline solutions can be predicted by Peleg model like with brown variety.of C. esculentus tubers. This swelling lead to enhance dehulling efficiency of tuber but caused soluble solute loss overall at the highest temperature of soaking in vitamin C solution. Like soaking in water, the constant of Peleg (k1) decrease with the increase of the temperature of soaking, whereas the constant of capacity of Peleg (k2) is approximately 0.018% for all the conditions. Dehulling efficiency also increased with increasing temperatures (65% at 20°C to 70% at 60°C) for tiger nut tubers soaked in water (0 g/L), dehulling efficiency appeared most strongly affected by concentrations and temperatures of soaking solutions. Like dehulling efficiency, ascorbic solutions has given the best results in term of reduction of microbial load compared to the other soaking solutions. This reduction is considerable at the higher temperatures, reaching a maximum of 4.8 log reduction. Soaking and dehulling treatments gave to black tiger nut tuber effective decontamination in term of microbial load and obtained good microbiological quality for final process.

Chemical Treatment of Black Tiger nut Tubers (Cyperus esculentus) Variety to Obtain a Bio-based Product

Black variety of tiger nut tubers (Cyperus esculentus) were differently processed in ascorbic acid and alkaline (Ca(OH)2 and Kanwa) solutions at different concentrations and temperatures. The effect of these treatments on the water content (swelling), soluble loss, dehulling efficiency and microbial load was investigated. Water content or swelling of the tiger nut soaked in acid and alkaline solutions can be predicted by Peleg model like with brown variety. This swelling lead to enhance dehulling efficiency of tuber but caused soluble solute loss overall at the highest temperature of soaking in vitamin C solution. Like soaking in water, the constant of Peleg (k1) decrease with the increase of the temperature of soaking, whereas the constant of capacity of Peleg (k2) is approximately 0.018% for all the conditions. Dehulling efficiency also increased with increasing temperatures (65% at 20°C to 70% at 60°C) for tiger nut tubers soaked in water (0 g/L), dehulling efficiency appeared most strongly affected by concentrations and temperatures of soaking solutions. Like dehulling efficiency, ascorbic solutions has given the best results in term of reduction of microbial load compared to the other soaking solutions. This reduction is considerable at the higher temperatures, reaching a maximum of 4.8 log reduction. Soaking and dehulling treatments gave to tiger nut tuber effective decontamination in term of microbial load and obtained good microbiological quality for final process.

Development of Accelerated Soaking Method for Mustard using Microwave-Assisted Heating

Mustard seeds are generally undergone the soaking process before use in any food application. But soaking mustard in water takes lots of time and energy. Therefore, the present investigation was carried out to study the soaking characteristics of mustard seed in different soaking conditions. The mustard seed was soaking in ambient water, hot water, and microwave heating applications. The initial moisture content of the mustard seed was found to be 12.64 % db. The moisture gain was found to be 55.46 % db in ambient water soaking after 360 min. In the hot water soaking, the moisture gain was estimated to be 68.33 % db, 80.40 % db, and 86.18 % db at 40°C, 50°C, and 60°C, respectively. The moisture gains in microwave-assisted soaking at 0.2, 0.4, 0.6, 0.8 and 1.0 W/g power densities level were found to be 67.77 % db, 67.80 % db, 103.28 % db, 115.08 % db, 131.51 % db, respectively after 10 min. The Peleg model was found to be suitable for describing the soaking characteristics of mustard seed at all soaking conditions with higher R2 values. Among all the soaking methods, microwave-assisted soaking showed the best soaking characteristics of mustard with less time consumption and with more amount of moisture gain. Therefore, microwave-assisted soaking of mustard seed may be recommended for soaking of mustard which is less time-consuming and energy-saving process

Kinetic Modeling of Essential Oil Extraction by Hydrodistillation of Xylopia aethiopica (Dunal) A. Rich Fruits from Congo-Brazzaville

The extraction kinetics of the essential oil of Xylopia aethiopica (Dunal) A. Rich by hydrodistillation was studied for modeling its process and optimizing its yield. The oils obtained, analyzed by GC/MS, consists mainly of pinenes, sabinene, myrenal, terpinene-4-ol, limonene. Experimental data were fitted into first and second order kinetics for a 2-steps extraction, washing and diffusion, of the phenomenological model, according to the hypothesis used. The essential oil which moves inner vegetable cells by diffusion and is extracted at the surface of the particle by washing with an extraction solvent. When the washing step is instantaneous compared to that of diffusion, the mechanism, which is under diffusion control, admits first order. Considering both washing and diffusion steps, kinetic order became 2, in agreement with the Peleg model. The Monod and Langmuir models also fitted experimental data. All these models validated by the experimental data with determination coefficients R2> 0.96 can be used for optimizing the extraction of the essential oil of Xylopia aethiopica (Dunal) A. Rich.

The Study of Sorption Characteristics of Dried Crab Stick Product Using Dynamic Vapor Sorption

The research delved into the sorption characteristics of dried crab stick products using dynamic vapor sorption (DVS). The obtained sorption isotherm data, including equilibrium moisture content (Me) and water activity (aw), were fitted with 6 different sorption isotherm models, such as Brunauer-Emmett-Teller (BET), Guggenheim-Anderson-Boer (GAB), Pickett-Modified BET, Adam and Shove, Blahovec-Yanniotis, and Peleg. The results showed that the Peleg model was the best-describing model with a coefficient of determination (R2), chi-square (χ2), root mean square error (RMSE), and standard error of estimate (SEE) ranging from 0.988 to 0.998, 0.719 to 4.349, 0.431 to 2.609 and 0.692 to 1.703, respectively. According to the classification of the shape of moisture sorption isotherm, the isotherm type III and II were found in this research for adsorption and desorption, respectively. The GAB and BET models were used to estimate monolayer moisture content (M0) of the sample and it was found that the M0 ranged from 3.65 to 5.36 % dry basis and 4.57 to 4.83 % dry basis for GAB and BET models, respectively. Blahovec-Yanniotis’s model was applied in this work to investigate the contribution of water and the result showed that the contribution of solution water played a major in the moisture changes of the sample during the adsorption and desorption process. Moreover, sorption isotherm data were modeled with 0 and 1st order reaction kinetics, and the results demonstrated that 0 order and 1st order models were the most appropriate model to describe moisture changes behavior of the sample at each relative humidity step for adsorption and desorption, respectively. HIGHLIGHTS The construction of sorption isotherms of dried crab stick product using dynamic vapor sorption GAB and BET models were used to estimate monolayer moisture content Peleg model was the most appropriate model to describe sorption behaviors of dried crab stick product Blahovec-Yanniotis provided the contribution of water information of dried crab stick during adsorption and desorption processes The application of reaction order kinetics could provide the information of moisture changing behaviors at each relative humidity step for adsorption and desorption processes GRAPHICAL ABSTRACT

Aplikasi Model Peleg untuk Analisa Rehidrasi Tekwan Kering pada Beberapa Suhu Perendaman

This study was aimed to apply Peleg Model to analyze rehydration of dried tekwan at several variations of water immersion temperature. The method used was descriptive and experimental of one factor treatment (Non Factorial), which was immersion temperature with four treatments level (30, 45, 70 and 90oC), each treatment was done triplicate. The parameter observed was moisture content at times of observation. The result showed that the Peleg Model coefficients (K1 and K2) were inversely affected by the temperature. The relationship was expressed into non-linear regression (polynomial) with R2 value of 0,973 and 0,988. It showed that the obtained Peleg model could be applied adequately for the rehydration of dried tekwan at some immersion temperature. The resulting model also met the statistical criteria with the largest SEE and MRE values 6.73% and 3.58%. The model could predict the dried tekwan rehydration best at the temperature of 30oC and 45oC with the smallest SEE and MRE values.

Isotermas de adsorção de umidade e cinética de secagem de sementes de trevo persa (Trifolium resupinatum L.) e trevo vesiculoso (Trifolium vesiculosum) ¬¬¬¬

The aim of this work was to obtain adsorption isotherms and to study the drying kinetics of persian clover (Trifolium resupinatum L.) and arrowleaf clover (Trifolium vesiculosum) seeds, in addition, fitting the experimental data by the predicted models of the literature. The equilibrium moisture content and the moisture adsorption behavior were found by isotherms curves at 40, 45 and 50 ºC, and the Peleg model was the most suitable. The drying kinetics was determined by thin layer assays in an air parallel flow dryer at all three temperatures. In addition, it was demonstrated the predominance of the falling drying rate period for the two species of seeds, and the critical moisture content values were approximately of 0.20 and 0.25 gwater gdry matter-1 for persian clover and arrowleaf clover seeds, respectively. The effective diffusivity values were estimated in ranges of values of 3.61×10-11 – 6.81×10-11 m² s-1 for persian clover and 6.76×10-11 – 1.15×10-10 m²s-1 for arrowleaf clover seeds and the temperature effect was expressed by an Arrhenius relation. Thus, drying kinetics confirmed the greater difficulty in moisture removal from the arrowleaf clover seeds, compared to the persian clover seeds drying, in agreement with the results obtained through adsorption isotherms.

Physiological potential of chickpea seeds

The chickpea crop is grown predominantly in the arid and semi-arid regions of the world. India is the largest producing country, in Brazil production is scarce, leading the country to import almost all of what is consumed. Grains are a good source of carbohydrates, proteins and even essential amino acids. One of the first steps towards profitable production is knowledge about the availability of high-quality seeds. The germination test, evaluates the formation of normal seedlings in ideal conditions, so it must be associated with vigor tests, rapid and uniform germination of the seeds, simulating adversities in the field. Among the tests used, accelerated aging and electrical conductivity are common, as well as the study of the water absorption curve by the seeds. Accelerated aging is based on high temperature and humidity, real stress conditions in the field or in storage. For chickpeas, it is recommended to use saturated saline solution, 24 h exposure, at 41 ºC and evaluation at the first count. The electrical conductivity is determined by the amount of leachate, the higher the values, the less vigor. The most suitable methodology is the use of 75 seeds, volume of 100 mL of water, during 30 h of soaking. The process of water imbibition by the seeds occurs according to a three-phase pattern. In studies with the species, there was no clear definition between the three phases. However, the Peleg model adjusted to the imbibition data of the analyzed cultivars. There are other efficient ways, not yet described, for evaluating the physiological potential in this species, among them the tetrazolium test, images from scanners and radiographs, or even magnetic resonance of seeds. Although these tools require expensive equipment, they can streamline and increase the accuracy of seed analysis.

Improvement of hydration properties of pectin/ alginate films with ZnO nanoparticles

This study aims to develop hydration properties of P/AG films by using ZnO nanoparticles. Pectin/ alginate/ ZnO nanoparticles (P/AG/ZnO-NPs) films are fabricated at various ZnO-NPs contents (0, 0.01, 0.05, 0.1 and 0.5 g/100g solution). The addition of ZnO-NPs at content 0.1 g/100g solution in the film decreases swelling degree (SD) from 327.98% to 110.12% and water vapor permeability (WVP) from 0.873 g.mm/m2.day.kPa to 0.358 g.mm/m2.day.kPa. Moisture sorption isotherm shows that P/AG/ZnO-NPs films should be used at lower than 86% RH. The Peleg model is the best model for predicting the equilibrium moisture content (EMC) of P/AG/ZnO-NPs films. Scanning electron microscope (SEM) micrographs of surface and cross section morphology of P/AG and P/AG with 0.1% ZnO-NPs films have indicated that there are interactions between ZnO-NPs and pectin-alginate matrix. Results have suggested that it would be favorable to prepare P/AG/ZnO-NPs film by using ZnO-NPs at the amount of 0.1 g/100g solution for food preservation.