Unveiling the Aromas and Sensory Evaluation of Hakko Sobacha: A New Functional Non-Dairy Probiotic Fermented Drink.

At the dawn of a food transition encouraging the consumption of healthy and sustainable non-dairy probiotic products, the development of a fermented functional drink based on Sobacha is considered. Sobacha is an infusion of roasted buckwheat seeds widely consumed in Asian countries for its health benefits. As fermentation improves the nutritional and organoleptic status of grains, the mixed fermentation process involved in the development of kombucha beverages (fermented sweet tea) is conducted by inoculating a symbiotic culture of bacteria and yeasts into the transposable matrix (Sobacha instead of tea). Sobacha, a healthy pseudo-cereal matrix with promising aromas, could be fermented to potentially develop an innovative drink, named "Hakko Sobacha". This neologism would reveal the fermented character of the infusion, Hakko meaning fermented in Japanese. Considering the beverage characterization, the kinetics of the volatile organic compound syntheses were determined using stir-bar sorptive extraction followed by gas chromatography coupled to mass spectrometry analysis. Odor-active compounds were theoretically calculated to estimate the flavor composition. Finally, sensory analyses highlighted the appreciation and preferences of the consumer towards the beverages. The fermentative yield differences observed between the two buckwheat concentration modalities tested seemed to be correlated with the sugar and nutrient levels available from the starch (buckwheat) matrix. Having characterized Hakko Sobacha, this study proposed the possibility of developing new beverages by monitoring the fermentative process. This should enable improved control and enhancement of their sensorial properties, which could in turn lead to greater customer acceptability.

Characterization of Aroma Active Compound Production during Kombucha Fermentation: Towards the Control of Sensory Profiles.

Since the sensorial profile is the cornerstone for the development of kombucha as a beverage with mass market appeal, advanced analytical tools are needed to gain a better understanding of the kinetics of aromatic compounds during the fermentation process to control the sensory profiles of the drink. The kinetics of volatile organic compounds (VOCs) was determined using stir bar sorptive extraction-gas chromatography-mass spectrometry, and odor-active compounds were considered to estimate consumer perception. A total of 87 VOCs were detected in kombucha during the fermentation stages. The synthesis of mainly phenethyl alcohol and isoamyl alcohol probably by Saccharomyces genus led to ester formation. Moreover, the terpene synthesis occurring at the beginning of fermentation (Δ-3-carene, α-phellandrene, γ-terpinene, m- and p-cymene) could be related to yeast activity as well. Principal component analysis identified classes that allowed the major variability explanation, which are carboxylic acids, alcohols, and terpenes. The aromatic analysis accounted for 17 aroma-active compounds. These changes in the evolution of VOCs led to flavor variations: from citrus-floral-sweet notes (geraniol and linalool domination), and fermentation brought intense citrus-herbal-lavender-bergamot notes (α-farnesene). Finally, sweet-floral-bready-honey notes dominated the kombucha flavor (2-phenylethanol). As this study allowed to estimate kombucha sensory profiles, an insight for the development of new drinks by controlling the fermentation process was suggested. Such a methodology should allow a better control and optimization of their sensory profile, which could in turn lead to greater consumer acceptance.

Microwave-assisted alkali hydrolysis for cellulose isolation from wheat straw: Influence of reaction conditions and non-thermal effects of microwave.

Microwave-assisted hydrolysis has been widely studied for cellulose fiber isolation, but the influence of reaction conditions and the microwave non-thermal effect are not well clarified. In this study, a series of well-designed experiments were carried out to measure the effects of reaction conditions including temperature, duration and alkali concentration. Compared to the other parameters, temperature was more relevant to the cellulose content in fiber. It could reach the maximum purity of 90.66 % when the temperature was up to 140 °C. Moreover, the existence of non-thermal effect of microwave has been confirmed through extensive determination and characterization of the fibers obtained from parallel controlled experiments conducted with or without microwave assistance. Approximately 50 %-75 % reduction in reaction time or 67 % of that in chemical costs would be realized under microwave with respect to traditional heating hydrolysis. Therefore, this work provides both deep insight and efficiency strategy into the microwave-assisted cellulose isolation.

Effect of heat treatments on the structure and emulsifying properties of protein isolates from cumin seeds ( Cuminum cyminum).

The effect of heat treatments (65, 75, 85, and 95 ℃, 30 min) on the structure and the emulsifying properties of cumin protein isolates were investigated. The fluorescence spectra analysis showed that the conformations were remarkably influenced by heat treatments. An increase in the ratio of α-helix in the secondary structure of heated cumin protein isolates was observed from the result of circular dichroism. Thermal treatments at different temperatures led to an increase in the surface hydrophobicity ( Ho) and a decrease in zeta potential ( ζ) of cumin protein isolates. Emulsifying activity index and emulsion stability index of heated cumin protein isolates were reduced at different protein concentrations (0.1, 0.5, and 1.0%), while the protein absorption in emulsions stabilized by heated cumin protein isolates gradually increased with heating temperature increasing. Moreover, both emulsions stabilized by native and heated cumin protein isolates showed pseudo-plastic fluid behavior and exhibited a decrease in their viscosities with proteins concentration increasing. But thermal treatments produced different effects on the flow behavior of emulsions formed by various protein concentrations, the flow index for heated cumin protein isolates emulsions increased at protein concentrations of 0.5 and 1.0%, but decreased at a concentration of 0.1%. These results might provide reference for the cumin protein processing and its application in food industry.

Effect of Organic Solvents on Microalgae Growth, Metabolism and Industrial Bioproduct Extraction: A Review.

In this review, the effect of organic solvents on microalgae cultures from molecular to industrial scale is presented. Traditional organic solvents and solvents of new generation-ionic liquids (ILs), are considered. Alterations in microalgal cell metabolism and synthesis of target products (pigments, proteins, lipids), as a result of exposure to organic solvents, are summarized. Applications of organic solvents as a carbon source for microalgal growth and production of target molecules are discussed. Possible implementation of various industrial effluents containing organic solvents into microalgal cultivation media, is evaluated. The effect of organic solvents on extraction of target compounds from microalgae is also considered. Techniques for lipid and carotenoid extraction from viable microalgal biomass (milking methods) and dead microalgal biomass (classical methods) are depicted. Moreover, the economic survey of lipid and carotenoid extraction from microalgae biomass, by means of different techniques and solvents, is conducted.

Beech wood Fagus sylvatica dilute-acid hydrolysate as a feedstock to support Chlorella sorokiniana biomass, fatty acid and pigment production.

This work evaluates the possibility of using beech wood (Fagus sylvatica) dilute-acid (H2SO4) hydrolysate as a feedstock for Chlorella sorokiniana growth, fatty acid and pigment production. Neutralized wood acid hydrolysate, containing organic and mineral compounds, was tested on Chlorella growth at different concentrations and compared to growth under phototrophic conditions. Chlorella growth was improved at lower loadings and inhibited at higher loadings. Based on these results, a 12% neutralized wood acid hydrolysate (Hyd12%) loading was selected to investigate its impact on Chlorella growth, fatty acid and pigment production. Hyd12% improved microalgal biomass, fatty acid and pigment productivities both in light and in dark, when compared to photoautotrophic control. Light intensity had substantial influence on fatty acid and pigment composition in Chlorella culture during Hyd12%-based growth. Moreover, heterotrophic Chlorella cultivation with Hyd12% also showed that wood hydrolysate can constitute an attractive feedstock for microalgae cultivation in case of lack of light.

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review.

Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed.

Characterization of sugar beet pectic-derived oligosaccharides obtained by enzymatic hydrolysis.

Three pectic oligosaccharides (POS) obtained by enzymatic hydrolysis of sugar beet pectin by combining endopolygalacturonase and pectinmethylesterase, were characterized using high performance liquid chromatography, thermogravimetric analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffraction. According to chromatographic analyses, POS are composed of mixture of polymers with different molecular weights and different galacturonic acid contents. The thermal analysis showed no major variation in thermal behavior regarding POS composition but showed that POS were more sensitive to thermal degradation than the parent pectin as well as the deesterified pectin. No change in composition of the gaseous products was obtained through TGA-FTIR analysis. The X-ray pattern of POS clearly indicated a considerable decrease in crystallinity when compared to the native pectin. Thus, thermal characterization of POS may have practical repercussions if the formulation in which POS is incorporated is submitted to a high temperature treatment.

Will isomalto-oligosaccharides, a well-established functional food in Asia, break through the European and American market? The status of knowledge on these prebiotics.

This critical review article presents the current state of knowledge on isomalto-oligosaccharides, some well known functional oligosaccharides in Asia, to evaluate their potential as emergent prebiotics in the American and European functional food market. It includes first a unique inventory of the different families of compounds which have been considered as IMOs and their specific structure. A description has been given of the different production methods including the involved enzymes and their specific activities, the substrates, and the types of IMOs produced. Considering the structural complexity of IMO products, specific characterization methods are described, as well as purification methods which enable the body to get rid of digestible oligosaccharides. Finally, an extensive review of their techno-functional and nutritional properties enables placing IMOs inside the growing prebiotic market. This review is of particular interest considering that IMO commercialization in America and Europe is a topical subject due to the recent submission by Bioneutra Inc. (Canada) of a novel food file to the UK Food Standards Agency, as well as several patents for IMO production.