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The demand for sugar-reduced, low-sugar, or even sugar-free food products is increasing. Sweet bakery products are the second main source of added sugar after sugary drinks. The reduction of sugar causes a loss of product quality, since sugar contributes to structure and flavour. The most common sugar replacers on the market are polyols, which act as sweet bulking agents. However, alternatives, which can be considered as ‘clean-label’ are in high demand. Sourdough technology was applied using the bi-functional lactic acid bacteria strain Leuconostoc citreum TR116. This strain is able to produce mannitol, which contributes to sweetness, and/or exopolysaccharides to compensate structure loss in sugar-reduced products. Besides the full-sugar biscuit (C1), biscuits reduced in sugar by 75% by wheat starch (C2) or by commercially available mannitol (C3) were considered as controls. Wheat starch as a sugar replacer created a lower biscuit firmness (− 10.7 N), while mannitol increased the hardness significantly (+ 12.9 N). Both sugar replacers caused less biscuit spreading and a poorer sensory profiles. The addition of sourdough (5% or 10%) in a sugar-reduced biscuit by wheat starch (C2) improved the viscoelastic properties, dough stickiness and dough hardness, as well as biscuit firmness. Furthermore, it contributed to colour (lowered the ΔE value) and increased sweetness and flavour intensity (+ 140%; + 139%). The predicted GI of C2-biscuits (73.5) were lower than C3-biscuits (80.8). Sourdough did not influence the release of reducing sugars during digestion. In conclusion, 10% sourdough incorporation represents a useful tool to overcome quality loss caused by the reduction of sugar by improving texture, taste and flavour.

Fungal pretreatment on lignocellulosic biomass has the advantages of being eco-friendly, having low operating cost, and producing no inhibitor. In this study, six white-rot fungi ( Trametes versicolor , Pleurotus ostreatus , Phanerochaete chrysosporium , Coriolopsis gallica , Pleurotus sajor-caju , Lentinula edodes ) were applied to corn stover pretreatment. Biomass degradation, production of enzymes, reducing sugar via hydrolysis, and ethanol yield via yeast fermentation were quantified during 30 days cultivation, and samples were taken every 5 days. Among six fungi, the highest lignin degradation was 38.29% at 30 days for P. sajor-caju pretreatment, the highest sugar yield was 71.24%, and the highest ethanol yield was 0.124 g g −1 corn stover under P. sajor-caju pretreatment for 25 days. The highest activities of laccase and manganese peroxidase were 29.22 and 10.22 U g −1 dry biomass, respectively, under T. versicolor pretreatment at 25 days. The highest levels of enzyme, sugar, and ethanol production are comparable or higher than what has been reported in previous literature. P. sajor-caju is one of the most widely worldwide cultivated mushrooms. The findings in this study show the potential to incorporate P. sajor-caju mushroom cultivation into corn stover pretreatment to enhance the production of a suite of products such as enzymes, sugars, and ethanol.

This study aimed to determine the effect of combinations of blanching parameters, including blanching temperatures ranging from 65 to 85 °C and duration times ranging from 2 to 10 min, on reducing sugars, asparagine, acrylamide, and color levels of fried potato chips. Response surface methodology was used to develop response surface equations to estimate these effects. These latter were evaluated before and after a 3-month storage period of potato tubers at 10 °C. It was found that certain blanching parameters resulted in optimal maximum reductions of 64.2, 49.8, and 61.3% for reducing sugar, asparagine, and acrylamide, respectively. Analysis of variance (ANOVA) determined that blanching time had a more significant impact than blanching temperature. The blanching time that resulted in maximum reductions of asparagine, reducing sugars—and ultimately acrylamide—were in the range of 8.8–9.7 min at 68.7–75.0 °C. ANOVA also determined that after the 3-month storage period of potato tubers, variations in blanching time and temperature did not result in any significant differences in acrylamide formation in fried chips. Blanching consistently improved the appearance of the fried chip products, indicated by increases in L* value and decreases in a* values. The relationship between acrylamide formation and a* value was linear (R2 = 0.839), while the relationship between acrylamide formation and L* value was not (R2 = 0.375).

This study researched the steam explosion effect catalysed by citric acid and sodium hydroxide on the chemical and structural properties of sugarcane bagasse and on the enzymatic hydrolysis process. Chemical and structural characterisation of raw and pretreated biomass was performed by reference methodologies for lignocellulosic materials, FTIR, XRD, TGA and SEM. Enzymatic hydrolysis was performed with a final volume of 20 mL consisting 3% sugarcane bagasse (dry weight), sodium citrate buffer 50 mM (pH = 5.0) and 1 g enzyme/100 g cellulose of Cellic ® Cetec 3 enzyme complex. The total reducing sugars were determined by a 3,5-dinitrosalicilic acid method. In explosion pretreatment catalysed by citric acid, a biomass was obtained with a lesser amount of hemicelluloses (16.16%), a higher initial degradation temperature and formation of cracks in fibre cell wall. Pretreated bagasse by NaOH steam explosion showed complete destructuring of fibre, lignin removal of 65% and hemicellulosic fraction preservation. Sugarcane bagasse obtained after NaOH steam explosion showed the highest production of reducing sugars (9.07 g L −1 ), which can be attributed to greater exposure of carbohydrate fraction promoted by lignin removal, since these parameters showed a strong negative correlation (r = −0.99, p < 0.05).

Recently peonies have become very popular cut flowers. As peony flowering period is short, long term cold storage could assure its prolonged supply and make long distance transport feasible. The effect of dry cold storage, of 8-hydroxyquinoline and nanosilver preservatives on the peony keeping qualities were tested on the most popular cultivar ‘Sarah Bernhardt’. The 12 week storage (0–1 °C) shortened flower longevity by 20%, to 8 days and no vascular blockages in the shoots were observed. However, the presence of callose, not considered as a blocking factor, was evident. The sucrose-containing preservatives with either 8-hydroxyquinoline or nanosilver did not extend the flower longevity but they increased flower diameters in both fresh and stored material. Generally, the soluble total and reducing sugars increased in senescing flowers in both non-stored and stored flowers, and they were lower after storage. The free proline increased ca. 20-times during cold storage and at the end of the vase life it remained generally higher in the stored than in fresh flowers. The level of hydrogen peroxide dropped after 12 weeks storage and its contents at the end of the vase life differed depending on the holding solution. Generally it was lower after storage. Storage increased the catalase activity which remained on higher levels in stored flowers from all holding solutions as compared to freshly cut flowers. A five-fold reduction in the peroxidase activity occurred during storage but its activities at the end of the vase life were similar in stored and non-stored flowers. The effects of nanosilver and 8-hydroxyquinoline were similar.

ObjectiveThe unique GH5 cellulase, AgCMCase, from Aspergillus glaucus CCHA was identified and characterized as having high cellulose and straw hydrolysis activities that were thermostable, pH stable and salt-tolerant. Therefore, it is a potential straw-degradation enzyme that can release reducing sugars in industrial applications. To increase the efficiency of the AgCMCase’ hydrolysis of straw to release simple sugars, response surface methodology (RSM) was introduced to optimize hydrolysis parameters such as pH, temperature, reaction time and enzyme dose.ResultsThe enzyme showed only one major protein band from the fermentation broth by the Pichia pastoris GS115 expression. The crude enzyme (without purification) showed a satisfactory capability to hydrolyze CMC-Na after 4 days of production. Here, the crude AgCMCase also showed cellulose and straw hydrolysis capabilities as assessed by scanning electron microscopic and Fourier-transform infrared spectroscopic analyses. A high-performance liquid chromatographic analysis demonstrated that the degradation of corn and rice straw by crude AgCMCase mainly produced glucose and cellobiose. Temperature, reaction time and enzyme dose were the significant variables affecting corn and rice straw degradation. After the optimization of RSM, a model was proposed to predict 1.48% reducing sugar yield with the optimum temperature (51.45 °C) and reaction time (3.84 h) from the straw degradation. The reaction of crude AgCMCase and rice straw in the optimized condition resulted in reducing sugar production of 1.61% that agrees the prediction.ConclusionOur findings suggest that the crude AgCMCase is suitable to be used in straw conversion.

Sugarcane is a significant primitive source of sugar and energy worldwide. The progress in enhancing the sugar content in sugarcane cultivars remains limited due to an insufficient understanding of specific genes related to sucrose production. The present investigation examined the enzyme activities, levels of reducing and non-reducing sugars, and transcript expression using RT-qPCR to assess the gene expression associated with sucrose metabolism in a high-sucrose sugarcane clone (GXB9) in comparison to a low-sucrose sister clone (B9). Sucrose phosphate synthase (SPS), sucrose phosphate phosphatase (SPP), sucrose synthase (SuSy), cell wall invertase (CWI), soluble acid invertase (SAI), and neutral invertase (NI) are essential enzymes involved in sucrose metabolism in sugarcane. The activities of these enzymes were comparatively quantified and analyzed in immature and maturing internodes of the high- and low-sucrose clones. The results showed that the higher-sucrose-accumulating clone had greater sucrose concentrations than the low-sucrose-accumulating clone; however, maturing internodes had higher sucrose levels than immature internodes in both clones. Hexose concentrations were higher in immature internodes than in maturing internodes for both clones. The SPS and SPP enzymes activities were higher in the high-sucrose-storing clone than in the low-sucrose clone. SuSy activity was higher in the low-sucrose clone than in the high-sucrose clone; further, the degree of SuSy activity was higher in immature internodes than in maturing internodes for both clones. The SPS gene expression was considerably higher in mature internodes of the high-sucrose clones than the low-sucrose clone. Conversely, the SuSy gene exhibited up-regulated expression in the low-sucrose clone. The enhanced expression of SPS in the high-sucrose clone compared to the low-sucrose clone suggests that SPS plays a major role in the increased accumulation of sucrose. These findings provide the opportunity to improve sugarcane cultivars by regulating the activity of genes related to sucrose metabolism using transgenic techniques.

Acidic carbonaceous solids were synthesized from mass pine alkali lignin via hydrothermal carbonization followed by sulfonation. Hydrothermal carbonization of lignin in the presence of acrylic acid (LAHC-SO 3 H) provided many more carboxylic groups than that in the absence of acrylic acid, allowing subsequent sulfonation to produce a highly active and stable catalyst for cellulose hydrolysis in the [BMIM]Cl-H 2 O solvent system. The hydrochar and catalyst were characterized using field emission scanning electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, thermal gravimetric analysis, Fourier transform infrared spectrometer, Brunauer–Emmett–Teller and acid–base titration. Results showed that a high acid content of 5.48 mmol/g, including carboxylic group (2.85 mmol/g), phenolic hydroxyl group (1.05 mmol/g) and sulfonic acid group (1.58 mmol/g), contributed significantly to the highly efficient hydrolysis of cellulose. Further, it was found that addition of trace water in [BMIM]Cl was favorable to cellulose hydrolysis. The highest yield (75.4%) of total reducing sugar (TRS) obtained in [BMIM]Cl-H 2 O at a mass ratio of 100:1 was more than twice that (36.1%) achieved in [BMIM]Cl without water; the corresponding reaction conditions were 50 mg of microcrystalline cellulose, 30 mg of catalyst, 1.0 g of [BMIM]Cl, 10 mg of H 2 O, reaction temperature of 130 °C and reaction time of 2 h. Furthermore, the TRS yield with 5 cycles for LAHC-SO 3 H was higher than 68.1%, and the catalytic activity of catalyst could be fully recovered (74.0% of TRS yield) easily by regeneration.

Soy protein is a valuable nutritional supplement for food and animal feed. While protein constitutes ~50 % of defatted soy flour (SF), it coexists with complex carbohydrates (30–35 %) which may have anti-nutritional effects. An enzymatic process can remove the carbohydrate and produce protein-enriched soy products. The hydrolysate with monomerized carbohydrates is valuable fermentation feedstock. In this study, Aspergillus niger and Trichoderma reesei enzymes were compared for use in the process. Effects of pH (3.2–6.4), temperature (40–60 °C), enzyme-to-SF ratio (0–2 ml/g) and SF loading (150–350 g/l) were evaluated for the enzymatic conversion of SF carbohydrate to reducing sugar ( Y RS ) and total soluble carbohydrate ( Y TC ) in the hydrolysate. Effects of these single factors and interactions between factors were investigated. Optimal pH and temperature were similar for both enzymes: pH 4.8 and 50–51 °C for Y TC , and pH 5.1–5.2 and 48–51 °C for Y RS . The two enzymes also gave similar protein contents in resultant soy protein concentrates, i.e., 74–75 % with 2 ml/g enzyme broth and 150 g/l SF, which were higher than the 64–68 % protein in commercial concentrates. A. niger enzyme was significantly more effective in carbohydrate conversion, achieving Y RS  = 75 % and Y TC  = 78 % with 2 ml/g enzyme and 150 g/l SF, higher than the Y RS (30 %) and Y TC (64 %) obtained with T. reesei enzyme. Monomerization was essentially complete in hydrolysate produced with A. niger enzyme.

Microalgae species including Chlamydomonas mexicana, Micractinium reisseri, Scenedesmus obliquus and Tribonema aequale were cultivated in batch cultures, and their biochemical composition was determined. C. mexicana showed the highest carbohydrate content of 52.6 % and was selected for further study. Sonication pretreatment under optimum conditions (at 40 kHz, 2.2 Kw, 50 °C for 15 min) released 74 ± 2.7 mg g⁻¹ of total reducing sugars (TRS) of dry cell weight, while the combined sonication and enzymatic hydrolysis treatment enhanced the TRS yield by fourfold (280.5 ± 4.9 mg g⁻¹). The optimal ratio of enzyme [E]:substrate [S] for maximum TRS yield was [1]:[5] at 50 °C and pH 5. Combined sonication and hydrolysis treatment released 7.3 % (27.1 ± 0.9 mg g⁻¹) soluble protein of dry cell weight, and further fermentation of the dissolved carbohydrate fraction enhanced the soluble protein content up to 56 % (228.4 mg g⁻¹) of total protein content. Scanning and transmission electron microscopic analyses indicated that microalgae cells were significantly disrupted by the combined sonication and enzyme hydrolysis treatment. This study indicates that pretreatment and subsequent fermentation of the microalgal biomass enhance the recovery of carbohydrates and proteins which can be used as feedstocks for generation of biofuels.