Increase In Sugar Content Research Articles

Dissecting the Genetic Architecture of Carbon Partitioning in Sorghum Using Multiscale Phenotypes

Carbon partitioning in plants may be viewed as a dynamic process composed of the many interactions between sources and sinks. The accumulation and distribution of fixed carbon is not dictated simply by the sink strength and number but is dependent upon the source, pathways, and interactions of the system. As such, the study of carbon partitioning through perturbations to the system or through focus on individual traits may fail to produce actionable developments or a comprehensive understanding of the mechanisms underlying this complex process. Using the recently published sorghum carbon-partitioning panel, we collected both macroscale phenotypic characteristics such as plant height, above-ground biomass, and dry weight along with microscale compositional traits to deconvolute the carbon-partitioning pathways in this multipurpose crop. Multivariate analyses of traits resulted in the identification of numerous loci associated with several distinct carbon-partitioning traits, which putatively regulate sugar content, manganese homeostasis, and nitrate transportation. Using a multivariate adaptive shrinkage approach, we identified several loci associated with multiple traits suggesting that pleiotropic and/or interactive effects may positively influence multiple carbon-partitioning traits, or these overlaps may represent molecular switches mediating basal carbon allocating or partitioning networks. Conversely, we also identify a carbon tradeoff where reduced lignin content is associated with increased sugar content. The results presented here support previous studies demonstrating the convoluted nature of carbon partitioning in sorghum and emphasize the importance of taking a holistic approach to the study of carbon partitioning by utilizing multiscale phenotypes.

Effects of Glucose and Corn Syrup on the Physical Characteristics and Whipping Properties of Vegetable-Fat Based Whipped Creams.

The aim of this work is to evaluate the effects of glucose and corn syrup on the physical characteristics and whipping properties of whipped creams. The interfacial protein concentration and apparent viscosity of emulsions increased with an increasing sugar concentration. In whipped creams, a shorter optimum whipping time (top), higher fat coalescence degree, higher firmness and higher stability were detected as sugar concentration increased. The partial coalescence degree, overrun and firmness of whipped cream with 30 wt% glucose reached 76.49%, 306% and 3.82 N, respectively, significantly (p < 0.05) higher than those (67.15%, 235% and 3.19 N) with 30 wt% corn syrup. Compared with glucose at the same sugar concentration, higher interfacial protein concentration and less-shaped aggregates and coalescences were observed for the emulsions upon the addition of corn syrup, which caused a lower degree of fat coalescence and a lower firmness of whipped cream. The differences could be explained by the presence of maltodextrin (MDX) in corn syrup, which protects absorbed protein throughout freezing and retards the formation of a continuous network during whipping. As a result, the addition of sugars could well improve stability of emulsion, firmness and foam stability of whipped cream efficiently. With a 25–30 wt% sugar addition, even if there was a lower partial coalescence degree and firmness compared with glucose, whipped cream with corn syrup exhibited relatively good stability. These results suggest that MDX improves the stability of emulsion and, thus, has a potential use in low-sugar whipped cream.

Effects of Water Stress, Defoliation and Crop Thinning on Vitis vinifera L. cv. Solaris: Part I: Plant Responses, Fruit Development and Fruit Quality.

Viticultural practices and irrigation have a major impact on fruit development and yield, and ultimately on must quality. The effects of water deficit (WD), defoliation (Def), and crop-thinning (CT) on Solaris plants and fruit development, as well as on the chemical composition of grape juice were investigated. WD was induced at three periods during fruit development (pre-veraison, veraison, and ripening) in pot-grown plants, while Def and CT were carried out on field-grown plants. Environmental and vegetative parameters were monitored during the experiments. The bulk chemical composition of the fruits was determined in juice by Fourier Transform-Infrared (FT-IR) spectroscopy throughout fruit ripening and at final harvest. The results showed that WD reduced soil water content and leaf water status. CT significantly reduced yield per vine, but increased cluster size. Mid to late WD reduced soluble solids by 1%. CT increased sugar content in juice, while Def decreased sugar accumulation. Total acids were higher in the juice from the field vines. Yet, CT lowered malic and tartaric acids. Def increased tartaric acid. Ammonia and alpha amino nitrogen were higher in the juice from pot-grown vines, while pH was lowered by Def and raised by CT. It is concluded that Solaris has a remarkable ability to tolerate and recover from WD. CT and Def significantly affected the bulk chemical composition of grapes in terms of total acidity and sugar accumulation, with CT grapes having the highest sugar content and the lowest total acidity and Def the opposite.

Stability, structure, and antioxidant activity of astaxanthin crystal from Haematococcus pluvialis

AbstractCrystallized anthaxanthin was prepared through the cleaning crystallization method and the stabilities during thermal, lighting, and pH treatment, and antioxidant activities in vitro were evaluated. The structural characterizations of astaxanthin crystal were verified by 1H, 13C NMR, and XRD analysis. The stability data showed that the astaxanthin crystal was more sensitive to heat, light, and pH compared to oleoresin. The sucrose had no outstanding influence on the astaxanthin crystal, while the stability of astaxanthin oleoresin slightly increased with the increase of sugar concentration. The XRD and nuclear magnetic resonance spectra elucidated that the astaxanthin crystal was all trans structure. The astaxanthin crystal showed the dominant 1,1′‐diphenyl‐2‐picrylhydrazyl (IC50 18.65 μmol L−1), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt˙+(21.1 μmol L−1), •OH (IC50 49.46 μmol L−1) and ferric reducing antioxidant power (IC50 81.60 μmol L−1) activities. The investigated results would be helpful for improving the development of astaxanthin crystal in food products.

Effects triggered by foliar selenium application on growth, enzyme activities, mineral nutrients and carbohydrates in lettuce under an aquaculture system

Se has beneficial effects on plants, through the stimulation of plant productivity, the reduction of abiotic stresses, and the improvement in N metabolism. Therefore, we investigated the effect of the foliar application of different concentrations of Se (0, 4, 8 and 16 μmol L−1) on lettuce plants grown in an aquaponics system (fish water) compared with a control (conventional soilless fertigation). The NO3- concentration supplied by the fish water was 47% of the control solution. The results showed a reduction in the fresh weight of lettuce plants irrigated with the fish water mixture treatment, along with an increase in sugar concentration. However, the application of Se at 4 and 16 μmol L−1, prompted a relief of this stress, reducing both lipid peroxidation and the sugar content, and increasing the nitrate concentration. In addition, in the case of the highest concentration of Se (16 μmol L−1), the values of nitrate were comparable those control plants. We show the importance of sprayed Se in increasing the efficiency of N utilization, in addition to lessening environmental issues for aquaponics culture.

Thinning of cluster improves berry composition and sugar accumulation in Syrah grapes

The sugars in grapes are crucial determinants of superior enological characteristics and product value. Recent research revealed that cluster thinning (CT) can increase sugar content and further modify the grape composition. This study examined the effects of cluster thinning at veraison on berry soluble sugar, organic acid, phenolic compound and sugar unloading-related gene expression of Syrah grapes. The effects of three CT levels on grape composition were investigated over two growing seasons. Two clusters per shoot remained (CT1) and one cluster per shoot remained (CT2) was compared with a control (CK, three clusters per shoot remained usually). Results showed that cluster thinning significantly improved the reducing sugar and soluble solids content of the CT2 group. Meanwhile, hexose (glucose and fructose), total anthocyanin and tannin contents in the CT group were significantly higher than in the control group at harvest for both vintages. In addition, under the CT treatments, the titratable acid and malic acid contents were decreased, but no effects on tartaric acid and citric acid contents were observed. At harvest, CT2 was the most significant treatment for increasing VvHTs (VvHT2-3, 5 and 6) expression, followed by CT1. Moreover, correlation analysis results show that VvSUC11, VvSUC12, VvcwINV, VvSS and VvHT5 were positively correlated with hexose and reducing sugars. Our results suggested that the remaining one cluster per shoot (CT2) may be useful for increasing the soluble sugar and improving grape composition in cool climate regions.

Microwave-assisted enzymatic hydrolysis to produce xylooligosaccharides from rice husk alkali-soluble arabinoxylan

The prebiotic properties of xylooligosaccharides (XOS) and arabino-xylooligosaccharides (AXOS) produced from rice husk (RH) using microwave treatment combined with enzymatic hydrolysis were evaluated. The RH was subjected to microwave pretreatment at 140, 160 and 180 °C for 5, 10 and 15 min to obtain crude arabinoxylan (AX). Increasing microwave pretreatment time increased sugar content. Crude AX was extracted with 2% (w/v) sodium hydroxide at 25 °C for 24 h and used as a substrate for XOS production by commercial xylanases. Results showed that oligosaccharides produced by Pentopan Mono BG and Ultraflo Max provided xylobiose and xylotriose as the main products. AXOS was also present in the oligosaccharides that promoted growth of Lactobacillus spp. and resisted degradation by over 70% after exposure to simulated human digestion.

Multi-omics approaches identify a key gene, PpTST1, for organic acid accumulation in peach.

Organic acid content in fruit is an important determinant of peach organoleptic quality, and undergoes considerable variations during development and maturation. However, its molecular mechanism remains largely unclear. In this study, an integrative approach of genome-wide association studies and comparative transcriptome analysis was applied to identify candidate genes involved in organic acid accumulation in peach. A key gene, PpTST1, encoding tonoplast sugar transporter, was identified and the genotype of PpTST1 with a single-base transversion (G1584T) in the third exon that leads to a single amino acid substitution (Q528H) was associated with a low level of organic acid content in peach. Overexpression of PpTST1His resulted in reduced organic acid content along with increased sugar content both in peach and tomato fruits, suggesting its dual function in sugar accumulation and organic acid content reduction. Two V-type proton ATPases interacted with PpTST1 in a yeast two-hybrid assay. In addition, the G1584T transversion appeared and gradually accumulated during domestication and improvement, which indicated that PpTST1 was under selection. The identification and characterization of PpTST1 would facilitate the improvement of peach fruit quality.

Biochar in manure can suppress water stress of sugar beet (Beta vulgaris) and increase sucrose content in tubers

Increased soil drought events threaten the yields of sugar beet (Beta vulgaris L.) and other staples of arable production in central Europe. In this study we evaluated soil moisture and nutrients as impacted by a two and five % (wt) addition of biochar, manure and their blend to a loamy-sand Regosol. Cyclical soil drought was achieved by the controlled reduction of watering by 75% in pot experiments. Ongoing soil moisture and nutrient measurements were taken, and physiological parameters of sugar beet plants were analysed three weeks after the induced drought. At the end of the experiment (16 weeks) plants were harvested and their mass assessed, as well as their nutrient, pigment and sugar contents. In contrast to the addition of manure, soil volumetric water contents were two to three times greater after biochar amendment, compared to the control soil. Porewater analysis revealed that nutrient leaching (e.g., NO3−, K+) from manure addition to soil was reduced when biochar was blended in (by ≤86% compared to manure alone). Crop analysis showed that leaf gas exchanges were moderated during drought following soil amendment, and leaf and tuber yields were increased furthest when combined biochar-manure blends were applied (> 2-times compared to the control). Perhaps most importantly, the advantageous soil conditions induced by the combined biochar and manure addition also resulted in significantly increased sugar contents in plants (2.4-times) pointing to immediate practical applications of these results in the field.

Extreme sugar accumulation in late fig ripening is accompanied by global changes in sugar metabolism and transporter gene expression.

Female fig (Ficus carica L.) fruit are characterized by a major increase in volume and sugar content during the final week of development. A detailed developmental analysis of water and dry matter accumulation during these final days indicated a temporal separation between the increase in volume due to increasing water content and a subsequent sharp increase in sugar content during a few days. The results present fig as an extreme example of sugar import and accumulation, with calculated import rates that are one order of magnitude higher than those of other sugar‐accumulating sweet fruit species. To shed light on the metabolic changes occurring during this period, we followed the expression pattern of 80 genes encoding sugar metabolism enzymes and sugar transporter proteins identified in fig fruit. A parallel comparison with male fig fruits, which do not accumulate sugar during ripening, highlighted the genes specifically related to sugar accumulation. Tissue‐specific analysis indicated that the expression of genes involved in sugar metabolism and transport undergoes a global transition.

Advancing knowledge about restricted irrigation strategies on commercial peach plantation under Mediterranean condition

This study was conducted to investigate the effects of different restricted irrigation strategies on peach trees. Sustainable and regulated deficit irrigation treatments were applied during the 2018/2019 production season in a commercial plot of “Bénédicte” variety located at the Atlas Mountain’s region of Morocco. Five different treatments were tested: T1, T2 and T3 with an application of respectively 125% (over-irrigation), 100% (control) and 75% (deficit-irrigation) of Crop Water Requirement (CWR) throughout the whole crop cycle; These treatments were classified under Sustainable Deficit Irrigation treatments (SDI). Regulated Deficit Irrigation treatments (RDI) comprising of treatments T4, and T5 which correspond respectively to applications of 75% ETc and 50% ETc during the pit hardening stage (PH), and 100% ETc during the rest of the cycle. The results showed that deficient irrigation treatments had no effect on vegetative growth parameters.A downward trend in average fruit weight and size at harvest was observed in the T3 treatment. A significant increase in sugar content was observed in T3 and T5 compared to the control T2. With regard to biochemical parameters, the deficient treatment (T5) recorded the highest proline content in response to water stress, followed by T3 and T4. Therewas no significant difference between the crop yields under SDI and RDI treatments, but T4 produced arelatively higher yield of 47 T/Haamong the treatments.Thisled to the water use efficiency (WUE) performance ranking: T3 with 10.63 kg/m3, T4 (75% PH) was in second place with a WUE of 9.6 kg/m3, finally T5 with an efficiency of 9.35 kg/m3.

Uticaj biopolimernih premaza na stabilnost skladištenja osmotski dehidriranih pečuraka

The main aim of this research was to apply biopolymer coatings on osmotically dehydrated mushrooms and monitor their quality during storage. Mushrooms were osmotically dehydrated in sugar beet molasses (80% dry matter) under optimized conditions (45 °C for 5 hours), as previously reported elsewhere. Two different biopolymers were chosen: chitosan, a polysaccharide polymer, and zein, a protein polymer. A non-treated mushroom sample was chosen as a control sample. The mushroom samples were analysed for sugar and protein content, as well as water loss and microbiological profile. An increase in sugar content was the most noticeable in the osmotically dehydrated mushrooms compared to the control sample due to the use of molasses as a hypertonic solution. The contribution of used biopolymer coatings to the sugar and protein content of the coated and osmotically treated mushrooms was negligible. Chitosan coating contributed to better storage stability of treated mushrooms by lowering the moisture loss and microbial count. For this reason, chitosan treated sample was chosen for further examination related to the evaluation of its baking potential as a filling in a traditional stuffed pie-like layered bakery product-burek. Burek was stuffed with fresh mushrooms, osmotically treated mushrooms or osmotically treated mushrooms coated with chitosan. The sensorial assessment proved that control burek and burek samples with osmotically dehydrated mushrooms coated with chitosan were the most preferred groups based on odour and overall impression.

Uticaj biopolimernih premaza na stabilnost skladištenja osmotski dehidriranih pečuraka

The main aim of this research was to apply biopolymer coatings on osmotically dehydrated mushrooms and monitor their quality during storage. Mushrooms were osmotically dehydrated in sugar beet molasses (80% dry matter) under optimized conditions (45 °C for 5 hours), as previously reported elsewhere. Two different biopolymers were chosen: chitosan, a polysaccharide polymer, and zein, a protein polymer. A non-treated mushroom sample was chosen as a control sample. The mushroom samples were analysed for sugar and protein content, as well as water loss and microbiological profile. An increase in sugar content was the most noticeable in the osmotically dehydrated mushrooms compared to the control sample due to the use of molasses as a hypertonic solution. The contribution of used biopolymer coatings to the sugar and protein content of the coated and osmotically treated mushrooms was negligible. Chitosan coating contributed to better storage stability of treated mushrooms by lowering the moisture loss and microbial count. For this reason, chitosan treated sample was chosen for further examination related to the evaluation of its baking potential as a filling in a traditional stuffed pie-like layered bakery product - burek. Burek was stuffed with fresh mushrooms, osmotically treated mushrooms or osmotically treated mushrooms coated with chitosan. The sensorial assessment proved that control burek and burek samples with osmotically dehydrated mushrooms coated with chitosan were the most preferred groups based on odour and overall impression.

Determination and assessment of the most potent precursors of advanced glycation end products in baklava and Turkish delight by HPLC

This study aims to investigate the glyoxal (GO), and methylglyoxal (MGO), and the effect of the types of sugar components on GO and MGO formation in Turkish delight and baklava. The values of GO and MGO ranged from 326 to 1842 µg/100 g, and from 31 to 517 µg/100 g in Turkish delight, respectively. The values of GO and MGO in baklava ranged from 344 to 815 µg/100 g, and between 19 and 358 µg/100 g, respectively. One of the baklava samples may contained high fructose corn syrup (HCFS) given the presence of significantly higher amount of MGO than that of other samples. Increased sugar concentration, processing time, storage, and HCFS in Turkish delight and baklava may affect the GO and MGO formations. Longer storage time may influence the increase of MGO formation in Turkish delight. Therefore, these products should be consumed less or formulated with agents that reduce AGEs.

Оценка кристаллогенной активности меда северных территорий Нижегородской области в различных разведениях

Crystallization of honey is one of its main properties. The component composition of honey has been studied for a very long time, but there are no express methods for examining its characteristics. For this reason, the issue of finding innovative methods for assessing the quality and safety of bee honey remains relevant at the present time. The aim of the study was to evaluate the effect of various honey dilutions on the crystallization of a model crystal-forming solution. Twenty samples of polyfler honey collected from apiaries located on the territory of the Shakhunya district of the Nizhny Novgorod region in the summer served as the material for the study. 4 samples were formed from each collected honey sample, the mass of each of which was 0.1 g, then homogenization of all samples was carried out. By adding an appropriate amount of saline solution to the honey samples, the following dilutions were obtained: 1:4, 1:8, 1:16, 1:32. A control sample representing 0.9% sodium chloride solution was also used. 100 μl of substrate from each sample was applied to a slide and dried in vivo. Facias were analyzed by microscopy using qualitative and quantitative criteria. It was found that in micro-preparations of diluted honey, the density of crystalline elements monotonically increases from the minimum dilution to the maximum. This is due to the high concentration of carbohydrates in honey, which are known inhibitors of crystallization. The use of this testing method during the examination will allow to identify the presence of honey adulterants with artificially increased sugar content.

FOAMING PROPERTIES OF MODEL SYSTEMS BASED ON WHEY

Background. One of the opportunities to expand the range and increase the share of desserts with a foamstructure is the use of multifunctional semi-finished products, the basis for which can be used protein-carbohydrate raw milk, in particular based on whey. Technologies for more than 100 names of products and semi-finished products using whey, the most of which have a liquid or condensed structure, have been developed.Studies on the possibility of developing dry semi-finished products are isolated. The aim of the articleis to study the functional and technological properties, in particular the foaming ability and stability of the semi-finished foam for whipped dessert products, depending on the ratio of its main prescription components. Materials and methods. For the study the whey dairy dry whey (WDDW) according to DSTU 33958–2016, dry cranberry extract (CE) TM Health Linkwere used. The foaming properties of the samples, namely the foaming ability (FA) and the stability of the foam (SF) were determined by the Lurie method. Results. The obtained solutions of reduced WDDW with different protein content showed certain foaming properties. The maximum manifestation was determined by the protein content of 5.8–6.5 % and temperature 5 ºC. The maximum value of foaming ability (FA) and foam stability (FS) model systems acquire the content of CE 13–18 %, which corresponds to pH 4.9–4.4. It is proved that with increasing sugar content in the range of 5–15 % FA increases by 20–25 %, the stability of the foam is almost unchanged.So, it is envisaged to use guar gum in the amount of 1 % by weight of the main components as a stabilizer. The maximum value of the FA system acquires at the beating speed (180–240) · 60s¹. Conclusion. The maximum foaming properties are shown by the semi-finished product for whipped dairy desserts, which contains: reduced WDDW with a protein content of 5.8–6.5 %, the cranberry extract 13–18 %, sugar 5–15 %. Technological parameters, according to which the maximum manifestation of foaming properties is observed, are the temperature of 5ºСand the beating speed (180–240) · 60 s¹.

Influence of agricultural techniques on yield and quality of grapes and wine

Under the conditions of changing biotic properties of terroir, it is relevant to establish the patterns of influence of different norms of the load of a grape bush in its own rooted and grafted culture on the quality of grapes, as well as the aesthetic and biological value of wine products in Russia. The objects of research were grapes and wine material of the Krasnostop AZOS variety in a grafted and rooted culture with variants of different load of shoots on the bush. The experience of studying the influence of various agrotechnical methods on the productivity of a grape plant and the quality of wine material was laid in the Anapo-Taman climatic zone of the Krasnodar Territory of Russia. The highest yield of the Krasnostop AZOS variety during the years of the study was obtained in the variant of own-rooted grape growing with its load of 36-40 shoots per bush. In our studies, there is a tendency to an increase in sugar content, and a decrease in the titratable acidity of grapes when growing vineyards of the Krasnostop AZOS variety in their own rooted culture. The most optimal ratio of sugar content and titratable acidity in the experiment was possessed by grapes from a variant of own-rooted culture with a load of 36-40 shoots/bush, here the glucoacedometric parameter was 4.36. In the studied variants, the largest amount of phenolic substances was found in wine material from self-rooted grapes with a load of 36-40 shoots per bush — 4130 mg/dm3. This had a positive effect on the organoleptic evaluation of this sample. The maximum total content of substances from a number of biologically active substances was found in wine from grape raw materials obtained from a grafted culture (134.9-147.9 mg/dm3). In 2018-2019, from the organoleptic side, wine materials from grapes of own-rooted culture proved to be of the highest quality. This advantage over the grafted crop was traced in all variants of rationing the load by the shoots of grape bushes.

Carbon reservoirs in shade-tolerant morphotype of Paubrasilia echinata are more susceptible to humidity and temperature changes than sun-tolerant morphotype

Given the eminent climate changes and the importance of carbon dynamics in the growth and survival of plants, we investigated how the non-structural carbohydrates – NSC – and cell wall polymers – CWP (cellulose, hemicellulose, and lignin) – from sun-tolerant and shade-tolerant plants will respond to changes in vapor pressure deficit (VPD) and temperature (temp.) of atmosphere predicted for the southeast region of Brazil for the next decades. We used plants of two morphotypes of Paubrasilia echinata as a biological model. This species presents intraspecific variations from each other in leaf morphology and growth concerning luminosity in the initial phase of growth. The small morphotype is shade-tolerant and the medium morphotype is tolerant to full sun. The work was carried out in greenhouses adjusted with the combination of the higher and lower VPD and temp., constituting 4 enviroments: 1) 0.4 KPa – 19.8 °C, 2) 0.5 KPa – 23.8 °C, 3) 2.0 KPa – 25.1 °C, and 4) 1.1 KPa – 14.9 °C. On day 125 after the start of the experiment, we determined the concentrations of NSC and CWP in the root, stem, and leaves. The shade-tolerant morphotype showed an increase in sugar concentration in the environment where the plants grew the most (2.0 KPa – 25.1 °C). In this same environment, the NSC concentrations of the shoot organs increased in the sun-tolerant morphotype. The 0.4 KPa – 19.8 °C reduced the cellulose and lignin concentrations of the shade-tolerant morphotype and promoted the hemicelluloses of the sun-tolerant morphotype. The NSC and CWP allocation proved to be more influenced by VPD and temp. variations in the shade-tolerant than the sun-tolerant morphotype. We conclude that warming and lower atmospheric humidity could inhibit the axial stem growth of sun-tolerant juvenile plants. Warming, regardless of atmospheric humidity variations, will not affect the cellulose and lignin levels of stem, and consequently, the wood quality of shade- and sun-tolerant plants. However, hemicelluloses concentrations of sun-tolerant plants may decline in a warmer and less humid atmosphere.

대추 열수 추출물의 항산화 및 영양학적 특성에 대한 Lactiplantibacillus plantarum 발효의 영향

The objective of this study was to evaluate the effect of fermentation by Lactiplantibacillus plantarum on the changes in antioxidant capacity and nutritional quality of jujube hot water extract. The dried jujubes were boiled at 100°C for 3-4 h (the 1st extract) and then another extract (the 2nd extract) was prepared with the same manner after removing the 1st extract. Both extracts were inoculated with L. plantarum, followed by fermentation at 37°C for 72 h. Change in the number of L. plantarum was measured during the fermentation, and the antioxidant capacity and nutritional quality of the both extracts and their corresponding fermented products were analyzed. The number of L. plantarum rapidly increased within 12 h, reaching the stationary phase, and was maintained until 72 h of fermentation. There was no significant difference in the sugar contents and total acidity among the 1st, the 2nd extracts and the fermented 1st extract but the increased sugar content in the fermented 2nd extract was observed. The fermentation by L. plantarum lowered the pH values, regardless of extracts. For nutritional components, no significant differences were observed between the 2nd extract and its fermented products. The antioxidant capacity and total polyphenol content of the extracts was not significantly different from their corresponding fermented products. These results indicate that the fermentation by L. plantarum did not have a profound effect on antioxidant capacity and nutritional components of jujube hot water extract. Thus, a further study is needed to improve the nutritional and functional qualities of jujube hot water extract by fermenting it with other lactic acid bacteria.

Optimization of oxalic and sulphuric acid pretreatment conditions to produce bio-hydrogen from olive tree biomass

This study investigated the best pretreatment conditions for olive tree biomass (OTB) to produce bio-hydrogen. The pretreatment conditions were optimized with response surface methodology for the dark fermentative hydrogen production to achieve maximum reducing sugar recovery and the independent variables were residence time (30–90min), temperature (100–140 °C), and acid concentration (0.5–3 %w/w for sulfuric and 5–10 %w/w for oxalic acid). Maximum reducing sugar obtained after sulfuric acid pretreatment and oxalic acid pretreatment at optimal pretreatment conditions were 37 g/L and 28 g/L, respectively. An approximately 20-fold increase in sugar concentration was achieved in pretreatment with sulfuric acid compared to the untreated control. The highest hydrogen yield was 0.83 and 0.91 mol H2/mol reducing sugar for oxalic acid pretreatment and sulfuric acid pretreatment, respectively. The results show that OTB has the potential to be used in bioenergy production.