Study of the effect of process parameters on the yield of fermentable sugar from red cocoyam (Xanthosoma sagittifolium) peels via acid and enzyme hydrolysis

The aim of this work is to study the acid and enzymatic hydrolysis of cocoyam peels using HCl, H2S04 acids and cellulase enzyme. The cellulase was secreted from Aspergillus Niger (A. niger) fungi. The proximate analysis of the substrate showed that cocoyam peel is a lignocellulosic biomass with a cellulose composition of 48%. The effect of the process parameters (time, temperature, acid concentration and pH) on the yield of glucose in acid and enzymatic hydrolysis of the cocoyam peel was respectively investigated. Maximum glucose yield of 44.5% was obtained after 3 days of enzymatic hydrolysis at 30°C and pH 5. The HCl acid hydrolysis showed a maximum glucose yield of 27.3% at 70°C, 5% HCl after 180 minutes. The glucose yield in H2S04 hydrolysis was relatively lower than that of the HCl with a maximum yield of 26.5% at 70°C, 5% H2SO4 after 180 minutes. In addition to, the functional groups present in the glucose synthesized from cocoyam ground peels and the standard glucose were evaluated using Fourier Transformed Infrared (FTIR). The FTIR results showed similarities in the functional groups present in both sugars. Cocoyam peel can be used for the production of glucose and further fermentative process to produce ethanol.

Study of the Effect of Process Parameters on the Yield of Fermentable Sugar from Tuber Peels Via Acid and Enzyme Hydrolysis

The aim of this work is to study the acid and enzymatic hydrolysis of water yam peels using HCl, H2S04 acids and cellulase enzyme. The cellulase was secreted from Aspergillus niger (A.niger). The proximate analysis of the substrate showed that water yam peel is a lignocellulosic biomass with a cellulose composition of 48%. The effect of the process parameters (time, temperature, acid concentration and pH) on the yield of glucose in acid and enzymatic hydrolysis of the water yam peel was respectively investigated. Maximum glucose yield of 44.5% was obtained after 3 days of enzymatic hydrolysis at 30°C and pH 5. The HCl acid hydrolysis showed a maximum glucose yield of 27.3% at 70°C, 5% HCl after 180 minutes. The glucose yield in H2S04 hydrolysis was relatively lower than that of the HCl with a maximum yield of 26.5% at 70°C, 5% H2SO4 after 180 minutes. In addition to, the functional groups present in the glucose synthesized from ground water yam peels and the standard glucose were evaluated using Fourier Transformed Infrared (FTIR) Spectroscopy. The FTIR results showed similarities in the functional groups present in both sugars. Yam peel can be used for the production of glucose and further fermentative process to produce ethanol.

Kinetic analysis of the fermentative process of mead with the addition of cupuaçu (Theobroma grandiflorum) pulp

Mead is historically one of the oldest drinks in the world. Its alcohol content can range from 4 to 14% and its formulation is basically honey, water, yeast and mineral salts, though other ingredients, such as fruits, can be added, thus giving rise to another version of mead known as melomel. Research has shown that fruity drinks have good consumer acceptability due to their alcohol content and their characteristic sweetness. Thus, the study aimed to produce mead with the addition of cupuaçu pulp and two different strains of Saccharomyces cerevisiae and Saccharomyces bayanus (T-58 and Red Star respectively), in order to perform a kinetic analysis of the fermentative process. For the elaboration of the mead, honey from the western honey bee (Apis melífera), cupuaçu pulp and yeasts were used, and the fermentation process lasted 15 days. The product was characterized through physicochemical and microbiological analyses. These analyses showed that the product is within the standards required by current Brazilian legislation. The monitoring of the kinetics of the mead fermentation allowed us to determine that the optimal time for this process is around 12 days, which is the point where there is a stabilization of the two strains in relation to the consumption of soluble solids and an increase in alcohol content. The two strains seem to be suitable for the production of mead; however, the results produced differ in alcohol content, resulting in drinks with distinct organoleptic characteristics.

Dark Fermentation Process Response to the Use of Undiluted Tequila Vinasse without Nutrient Supplementation

The technical feasibility of valorizing tequila vinasse (TV), a wastewater with high pollution potential, through the production of biogenic hydrogen via dark fermentation, has long been proven in diverse lab-scale reactors that were operated either in batch or continuous mode. However, such systems have mainly been tested with diluted streams and nutrient supplementation, hindering the techno-economic attractiveness of the TV-to-hydrogen concept at large scale. In this study, the feasibility of producing hydrogen from high-strength undiluted TV with no added extra nutrients was evaluated under batch mesophilic conditions. Additionally, the use of two different acidogenic inocula obtained either by heat or heat-aeration pretreatment was investigated to get a greater understanding of the effect of inoculum type on the process. The results obtained showed that the TV utilized herein contained macro- and micro-nutrients high enough to support the hydrogenogenic activity of both cultures, entailing average hydrogen yields of 2.4–2.6 NL H2/L vinasse and maximum hydrogen production rates of 1.4–1.9 NL H2/L-d. Interestingly, the consumption of lactate and acetate with the concomitant production of butyrate was observed as the main hydrogen-producing route regardless of the inoculum, pointing out the relevance of the lactate-driven dark fermentative process. Clostridium beijerinckii was ascertained as key bacteria, but only in association with microorganisms belonging to the genera Enterobacter and Klebsiella, as revealed by phylogenetic analyses.

Influence of Microencapsulation on Fermentative Behavior of Hanseniaspora osmophila in Wine Mixed Starter Fermentation

In recent years, as a consequence of the re-evaluation of the role of non-Saccharomyces yeasts, several studies have been conducted on the use of controlled mixed fermentations with Saccharomyces and different non-Saccharomyces yeast species from the winemaking environment. To benefit from the metabolic particularities of some non-Saccharomyces yeasts, the management of a non-Saccharomyces strain in mixed fermentation is a crucial step, in particular the use of procedures addressed to increase the persistence of non-Saccharomyces strains during the fermentative process. The use of microencapsulation for cell immobilization might represent a strategy for enhancing the competitiveness of non-Saccharomyces yeasts during mixed fermentation. This study was aimed to assess the fermentative performance of a mixed starter culture, composed by a wild Hanseniaspora osmophila strain (ND1) and a commercial Saccharomyces cerevisiae strain (EC1118). For this purpose, free and microencapsulated cells of ND1 strain were tested in co-culture with EC1118 during mixed fermentations in order to evaluate the effect of the microencapsulation on fermentative behavior of mixed starter and final wine composition. The data have shown that H. osmophila cell formulation affects the persistence of both ND1 and EC1118 strains during fermentations and microencapsulation resulted in a suitable system to increase the fermentative efficiency of ND1 strain during mixed starter fermentation.

Pu-erh tea: Fermentative process as a potentialized of sensory aspects and bioactive profile – a review

Pu-erh is a fermented Chinese tea with characteristics of mild, woody flavor and dark red color. The preparation of the tea starts from leaves of Camellia sinensis in natura that undergo a drying in the sun. Its classification is given in two categories: a raw tea similar to green tea and a matured tea that is fermented. Matured tea has a higher market value due to the processes involved in manufacturing, especially in terms of aging. Pu-erh has numerous benefits for human health, which are closely related to the bioactive profile of the main chemical components of tea, being polyphenols, theabrownins, flavonols, polysaccharides, amino acids and alkaloids. The increasing introduction of Pu-erh tea in the diet of consumers results in the need to explore information associated with consumption through analysis of the available literature, addressing current scientific evidence. Therefore, the present review sought to elucidate the fermentative process of Pu-erh tea production, its chemical composition, its sensory aspects and health benefits.

Physical, chemical and microbiological characterization of cupuassu seed during fermentation

The cupuassu’s seeds are similar to cocoa, being possible to apply fermentative techniques used to obtain nibs and cupulate. The aim of this work to study the physicochemical transformations during the cupuassu´s seeds fermentation. For this purpose, frozen seeds from a pulp processing industry were fermented in three batches of 20 kg for seven days at room temperature. During the fermentation process, seed mass temperature, dimensions, density and composition of the kernels, color indexes (L*, C* and H*), microbiological analyzis (mesophiles, molds and yeasts), cut-proof, physicochemical analyzis (pH, acidity and glucose reducing sugars and non sucrose reduction) and centesimal composition (ashes, lipids, proteins and carbohydrates) were analyzed from triplicates. The results were expressed as dry basis. During the fermentations, the great temperatures were reached. The maximus were 43,44 and 47 ºC in three fermentations. It was observed during the fermentation process: seed darkening (L*) and color intensity reduction (Chroma), pH increase, sugar reduction and acidity reduction. The ash, lipid and protein contents were not significantly influenced by the fermentation time. According to the cut test, the kernels of 3rd fermentation, whose maximum temperature was higher, were classified as type 2 and the others as type 3. The values of apparent density, dimensions, mass and composition of seeds demonstrated that during the fermentation there was a decrease in volume with a higher proportion of cotyledon compared to testa. There was an increase in counts of total mesophiles aerobic microorganisms, molds and yeasts, during the fermentative process.

Insights on Monosaccharides and Bioethanol Production from Sweet Sorghum Stalks Using Dilute Acid Pretreatment

Sweet sorghum is a unique bioenergy crop that produces stalks with fermentable free sugars. The purpose of this study was to evaluate how the production of hemicellulosic saccharides and bioethanol from sweet sorghum stalks (SSS) can be influenced by a dilute sulfuric acid (H2SO4) pretreatment under different isothermal conditions. The bioethanol production from untreated SSS and pretreated solid phases was achieved through the Simultaneous Saccharification and Fermentation (SSF) process. A good SSS fractionation and an extensive hemicellulose hydrolysis into soluble saccharides were obtained, the most abundant hemicellulose-derived compounds present in the pretreated liquid phase being monosaccharides, with up to 17.22 g/L of glucose and 16.64 g/L of xylose in the pretreatments performed with 3% and 1% H2SO4 for 30 min at 134 °C, respectively. The SSF process of untreated SSS allowed a maximum bioethanol concentration of 9.78 g/L, corresponding to a maximum glucan conversion into ethanol of 49.8%. Bioethanol production from untreated SSS led to a higher bioethanol concentration and conversion than in the case of using acid pretreated solid phases obtained under the most severe conditions (with 3% H2SO4 for 30, 60 and 120 min at 134 °C), suggesting that, in the case of this biomass naturally rich in soluble sugars, the acidic pretreatment could negatively influence the fermentative process.

VARIOUS FACTORS AFFECT THE QUALITY OF FERMENTED CASSAVA STARCH

Fermented cassava starch is one of modified cassava starch products and used in many countries in several food products. The fresh extracted cassava starch is modified by a process of fermentation and sun drying by means the traditional methods. Several works have shown that fermentative process alters the starch granule, giving fermented starch its characteristics are different from those of the native cassava starch. The main difference between fermented cassava starch[A1] and native cassava starch reside in the expansion property. Understanding the transformation of physico-chemical properties of cassava starch during fermentation is important for controlling the production processes. This discourse refers to the several works that intend to chemically show the expansion property of fermented cassava starch, considered a chemically and enzymatically modified product, with acidic characteristics, perforated granules and high expansion capacity. Expansion is a natural characteristic of fermented cassava starch, defined as the growth rate of the dough during oven cooking, also referred to as expansion rate. The main aim of this discourse is to get a better understanding how to manage the production processes in order to achieve greater consistency in the quality of sour cassava starch.Â