Co-crystallization of Sucrose at High Concentration in the Presence of Glucose and Fructose

ABSTRACT: Co-crystallization of sucrose from a highly concentrated sucrose syrup (≤ 7% moisture, w/w) at 131 °C with 0, 5, 10, 15, and 20% of fructose, glucose, or a mixture of fructose and glucose was investigated. The crystallization of sucrose was delayed in presence of these lower molecular weight sugars. The DSC melting endotherm of co-crystallized samples exhibited a decrease in crystalline sucrose in the sample as a function of increased level of glucose and fructose. The mechanical strength of co-crystallized granules was found to be related to the moisture content and the amount of glucose or fructose content in the sample. The samples containing 10, 15, and 20% glucose in co-crystallized product demonstrated crystallization of glucose in its monohydrate form during 1 mo of storage.     

Effects of Anions and Cations on Sugar Utilization in Cucumber Juice Fermentation

ABSTRACT: :
The extent of glucose and fructose utilization during cucumber juice fermentation was affected differentially by the addition of 10 to 360 mM of selected anions (chloride, nitrate, sulfate, phosphate, acetate, lactate, and citrate) and cations (Na⁺, K⁺, NH₄⁺, Ca²⁺, Mg²⁺, and Mn²⁺). Inorganic anions generally suppressed utilization of both sugars, particularly at higher concentrations. Acetate and lactate increased utilization of fructose, but not glucose, while citrate increased utilization of both sugars. Of the cations tested, 10-60 mM Mn⁺² significantly (P < 0.05) increased utilization of both sugars, but higher concentrations reduced utilization, as compared with the control. Evidence indicates that brine composition can significantly influence sugar utilization during cucumber fermentation, and may be important in developing controlled fermentation strategies for brined cucumbers.     

Loss of Fuminosin B1 in Extruded and Baked Corn-Based Foods with Sugars

The objective of this work was to determine the effect of added sugars on fumonisin B₁ (FB₁) levels in baked corn muffins and extruded corn grits. Muffins containing added glucose had significantly lower FB₁ levels than muffins with sucrose, fructose, or no added sugar. Extrusion cooking of the grits resulted in significant (p< 0.05) reductions of FB₁ in all treatments relative to unextruded controls, but use of glucose resulted in greater reductions of FB₁ (45.3 to 71%) than did the use of fructose (29.5 to 53%) or sucrose (19.2 to 39%). When extrusion conditions were optimized, 92.1% loss of FB₁ was found when grits were extruded with glucose. Adding glucose to thermally processed food can result in a substantial reduction in FB₁ levels.     

Purification and Characterization of an α-L-Rhamnosidase from Aspergillus terreus of Interest in Winemaking

ABSTRACT: An enzyme with α-L-rhamnosidase activity was purified to homogeneity from a culture filtrate of Aspergillus terreus after growth in a medium containing L-rhamnose as the sole carbon source. The biosynthesis of this enzyme was repressed by glucose. The enzyme had a molecular mass of 96 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an isoelectric point of 4.6 as determined by analytical isoelectric focusing. The pH and temperature optima for the enzyme were found to be 4.0 and 44 °C, respectively. Using p-nitrophenyl-α-L-rhamnopyranoside as a substrate, the enzyme exhibited Michaelis-Menten kinetics with K_M and V_max values of 0.17 mM and 84 U/mg, respectively. The enzyme was inhibited competitively by L-rhamnose (K₁ 2.5 mM). Divalent cations such as Ca²⁺ Mg²⁺ Zn²⁺ and Co²⁺ stimulated the a-L-rhamnosidase activity, whereas this was inhibited by Hg2+ and Cd2+. Ethanol (12% v/v) and glucose (21% w/v) decreased enzyme activity by approximately 20%, while this was not affected by SO₂.     

Effects of inulin/oligofructose on the thermal stability and acid-induced gelation of soy proteins

ABSTRACT:  Differential scanning calorimetry (DSC) and dynamic oscillatory shear testing were performed to study the influence of inulin (Raftiline^® HP-gel and Raftiline^® ST-gel) and oligofructose (Raftilose^® P95) on the thermal stability and gelation (using glucono-δ-lactone [GDL] as a coagulant) of soy protein isolate (SPI) dispersions. Addition of 10% (w/v) inulin/oligofructose or sucrose increased ( P < 0.05) the peak denaturation temperatures ( T_m ) of 7S and 11S soy proteins in SPI dispersion (5%[w/v], pH 7.0) by an average of 1.9 and 2.3 °C, respectively. GDL induced SPI thermal gelation, and the gel rheology was affected by both the pH decline and the specific temperature of heating. Addition of inulin/oligofructose (8%, w/v) improved the gelling properties of preheated SPI dispersion (8%, w/v) coagulated with GDL, showing 14.4 to 45.6% increase ( P < 0.05) in gel rigidity ( G ' value) at the end of heating (81 °C). Microstructural examination revealed a denser protein cross-linking structure and reduced pore sizes in SPI gels containing inulin/oligofructose. In general, inulin was more capable of improving SPI gelation than oligofructose, suggesting that the degree of fructose polymerization in the fructans was of thermal and rheological importance.     

Investigation of Cashew Apple Juice as a Substrate for Single Cell Protein Production

Cashew juice was investigated for its ability to support the growth of Saccharomyces cerevisiae. A characteristic of the juice showed that it contained a mixture of fermentable sugars of which glucose, fructose and sucrose have been identified. Also the concentration of reducing sugars was as high as 15% w/v. Growth studies were carried out in a 7-L batch fermentor at a pH of 5.0 and 30°C with and without nutrient supplementation. The corresponding yields were 0.50 and 0.39 gram cells/gram reducing sugar consumed, respectively. While about 10% of the reducing sugar was consumed in the unsupplemented medium 43% was consumed in the medium with supplementation.     

Modelling the respiration rate of fresh-cut Annurca apples to develop modified atmosphere packaging

In this work, the effect of temperature, oxygen, red coloration process and post-harvest storage time on the respiration rate of fresh-cut Annurca apples was studied to properly develop modified atmosphere packaging. Our results showed that the red coloration process and the post-harvest storage time did not affect the respiration rate or the respiratory quotient of fresh-cut Annurca apples in the range of temperature studied (5–20 °C). A Michaelis–Menten-type equation, with the model constants described by means of an Arrhenius-type relationship, was used for predicting respiration rate on varying the temperature and O₂ concentration in the head space. The maximal respiration rate (mL kg h⁻¹) (RR_max) and the O₂% corresponding to     values estimated at the reference temperature (12.5 °C), i.e. the average of the experimental temperature ranges, were, respectively, 6.77 ± 0.1 mL kg⁻¹ h⁻¹ and 0.68 ± 0.07% v/v, and the activation energy of the aerobic respiration rate of fresh-cut Annurca apples was estimated at 51 ± 1 kJ mol⁻¹. The model works well to develop a modified atmosphere for fresh-cut Annurca apples.     

Optimization of Medium Composition for Cultivating Clostridium butyricum with Response Surface Methodology

ABSTRACT: Probiotic bacteria, such as some strains of Clostridium butyricum , have been frequently used as the active ingredient in functional foods. However, slow growth of the probiotic bacteria has been one of the big concerns for their potential commercial application. In the present study, a fractional factorial design was applied to investigate the main factors, namely, the concentrations of the glucose, tryptone, yeast extract, beef extract, cys-teine, (NH₄) ₂SO₄, NaCl, K₂HPO₄, and the medium initial pH that affected the growth of 1 probiotic strain, C. butyricum ZJUCB, currently preserved in our laboratory. Central composite experimental design and response surface methodology were adopted to derive a statistical model for optimizing the composition of the medium. The experimental results showed that the optimum medium for incubating the C. butyricum ZJUCB was composed of 2.44% (w/v) glucose, 2.08% yeast extract (w/v), 1% tryptone (w/v), 0.1% (NH₄)₂SO₄ (w/v), 0.1% NaHCO₃ (w/v), 0.02% MnSO₄. H₂O (w/v), 0.02% MgSO₄. 7H₂O (w/v), 0.002% CaCl₂ (w/v), and 2% agar (w/v) (if necessary) at pH 8.55. After incubation for 24 h in the optimum medium, the populations of the viable organisms could reach 10⁹ colony-forming units (CFU)/mL, which was 100 times higher than that incubated in the initial medium.     

Alginate- and gellan-based edible films for probiotic coatings on fresh-cut fruits

ABSTRACT:  Alginate- (2% w/v) or gellan-based (0.5%) edible films, containing glycerol (0.6% to 2.0%), N-acetylcysteine (1%), and/or ascorbic acid (1%) and citric acid (1%), were formulated and used to coat fresh-cut apple and papaya cylinders. Water vapor permeability (WVP) was significantly higher ( P < 0.05) in alginate films (0.30 to 0.31 × 10⁻⁹g m/Pa s m²) than in the gellan ones (0.26 to 0.27 × 10⁻⁹g m/Pa s m²). Addition of 0.025% (w/v) sunflower oil decreased WVP of gellan films (0.20 to 0.22 × 10⁻⁹ g m/Pa s m²). Water solubility of gellan and alginate films at 25 °C (0.47 to 0.59 and 0.74 to 0.79, respectively) and their swelling ratios (2.3 to 2.6 and 1.6 to 2.0, respectively) indicate their potential for coating high moisture fresh-cut fruits. Fresh-cut apple and papaya cylinders were successfully coated with 2% (w/v) alginate or gellan film-forming solutions containing viable bifidobacteria. WVP in alginate (6.31 and 5.52 × 10⁻⁹g m/Pa s m²) or gellan (3.65 and 4.89 × 10⁻⁹ g m/Pa s m²) probiotic coatings of papaya and apple, respectively, were higher than in the corresponding cast films. The gellan coatings and films exhibited better water vapor properties in comparison with the alginate coatings. Values > 10⁶ CFU/g B. lactis Bb -12 were maintained for 10 d during refrigerated storage of fresh-cut fruits, demonstrating the feasibility of alginate- and gellan-based edible coatings to carry and support viable probiotics on fresh-cut fruit.     

ANTIOXIDANT ACTIVITY AND QUALITY OF SOY ENRICHED APPLE BAR

Antioxidant activity of a soy enriched apple bar (SEAB) prepared from the pulp of culled apples and soy protein isolate (3%) was determined using a ferric reducing antioxidant power (FRAP) assay. The antioxidant activity was 8500 μM g⁻¹ FRAP and phenol content was 175 mg 100 g⁻¹. The soy enriched apple bar had 20 fold protein and 1.6 fold higher antioxidant activity than the plain apple bar. No significant change in antioxidant activity and total phenols was recorded during storage at ambient (22–31C) or low (4±1C) temperatures. The pectin, protein and ascorbic acid contents decreased while nonenzymatic browning and total sugars increased significantly with increase in storage periods. The product was organoleptically acceptable and microbiologically safe after 180 days of storage. A shelf stable soy enriched apple bar with high antioxidant activity, phenol content and sensorial quality can be an ideal source of dietary antioxidants.     

Inactivation of Listeria monocytogenes on Beef Bologna and Cheddar Cheese Using Polyvinyl-idene Chloride Films Containing Sorbic Acid

ABSTRACT: Polyvinylidene chloride (PVDC, Saran^R F-310) films containing sorbic acid (0%, 1.5%, and 3.0% w/v) were prepared with use of a solvent-casting method and were then placed between slices of commercially produced beef bologna that were previously surface-inoculated with L. monocytogenes at 10³ or 10⁵ CFU/g. In addition, cubes of commercial Cheddar cheese were surface-inoculated to contain 10³ or 10⁵ Listeria monocytogenes colony-forming units (CFU) /g and then wrapped with the sorbic acid-containing films. Films containing 1.5% and 3.0% (w/ v) sorbic acid prevented growth of L. monocytogenes on bologna slices with populations as much as 7.1 logs lower after 28 d of storage at 4 °C compared with the sorbic acid-free controls. In contrast, numbers of Listeria remained relatively stable on Cheddar cheese with populations decreasing < 1.3 logs after 35 d of storage. With use of the sorbic acid-containing films, common spoilage organisms were also inhibited on both products. After 28 d of contact with bologna and Cheddar cheese, these films retained 7% and 60% of their original sorbic acid content, respectively, with the control film retaining 85% of its original sorbic acid content. Given these findings, sorbic acid-containing films may be useful in enhancing the safety and shelf-life of ready-to-eat delicatessen products.     

CHARACTERIZATION OF DYE-SENSITIZED PHOTOOXIDATION OF MUSHROOM TYROSINASE

Dye-sensitized photooxidation was investigated as a nonthermal means to inactivate food quality-related enzymes, using mushroom tyrosinase as a model. Illumination of tyrosinase in the presence of either rose bengal or riboflavin resulted in an apparent first-order destruction of enzyme activity. Both dye and light were required, and photoinactivation was favored by increasing levels of dissolved oxygen. The rose bengal-sensitized photooxidation was generally more rapid than that caused by riboflavin (at 0.01% dye), with k_i values ranging from 0.74 to 1.66 h⁻¹ and 0.25 to 1.23 h⁻¹, respectively. First-order rate constants for photoinactivation decreased with decreasing temperatures (E_a was 8.4 to 12.2 kcal mol⁻¹ between 20° and 50°C), increasing protein concentration (0.175 to 1.40 mg⁻¹ ml), increasing sodium phosphate buffer concentration (10 to 200 m M) and increasing ionic strength (0.02 to 0.20). The dependence of enzyme photoinactivation rates on pH (between 6.0 and 9.0) resembled a titration curve with a pK of 7.5, and maximal rates were observed at pH 8.0–9.0.     

Influence of sodium and calcium ions on rheological behaviour of wheat glutenins extracted in alkaline ethanol solution

Wheat glutenins were extracted in alkaline aqueous solution containing 50% (v/v) ethanol and 0.025  m NaOH from the gluten residue after extraction using 70% (v/v) aqueous ethanol. Rheological behaviours of the solutions were investigated as a function of protein concentration and ion strength. Sodium (Na⁺) and calcium (Ca²⁺) ions have different influences on the rheological behaviour of the glutenin solution of 48 mg mL⁻¹. While addition of Na⁺ results in Newtonian fluids with a reduction in apparent viscosity in comparison with the salt-free solution, addition of Ca²⁺ leads to the formation of a viscoelastic network with enhanced shear-thinning. The solutions containing 0.2  m and 0.4  m Ca²⁺ exhibit yielding at low strain rates. The solution containing 0.6  m Ca²⁺ behaves as a pseudoplastic fluid with the appearance of two Newtonian plateaus at low and high strain-rate limits.     

Inulin and Sugar Contents in Helianthus tuberosus and Cichorium intybus Tubers: Effect of Postharvest Storage Temperature

ABSTRACT: Inulin, sucrose, fructose, and glucose contents in tubers of Helianthus tuberosus (Jerusalem artichoke) and Cichorium intybus stored at different temperatures (-18, 4, and 18 °C) after harvesting were followed. Inulin content in both tubers decreased during storage. In C. intybus this decrease was associated with increases in glucose and fructose contents. In H. tuberosus the fructan fraction having molecular weight between 800 and 1200 increased after sucrose reached its maximum content [1.3–10⁻¹ g(g d.w.)⁻¹] in tubers stored at 4 °C. Fructose-to-glucose ratio was followed in H. tuberosus tubers harvested at different times; samples from plants subjected to different fertilization treatments were used. This parameter can be used for choosing the harvest date since it is related to the disappearance of the fructan fraction having molecular weight higher than 1200.     

重组谷氨酸棒杆菌全细胞催化一步法合成高果糖浆

高果糖浆是一种可替代蔗糖的甜味剂,在食品和饮料行业应用广泛.该研究实现了经密码子优化的密苏里游动放线菌(Actinoplanes missouriensis)CICIM B0118(A)来源的葡萄糖异构酶在食品安全菌株谷氨酸棒杆菌(Corynebacterium glutamicum)13032中的异源表达,构建了重组...     

THE EFFECTS OF USING ALTERNATIVE SWEETENERS TO SUCROSE ON ICE CREAM QUALITY

In this study, seven different ice cream samples were produced using sucrose, high fructose corn syrup (HFCS), glucose syrup (GS), honey, sucrose  +  GS, sucrose  +  HFCS and sucrose  +  honey mixtures (1/1). The ice cream samples containing only sucrose were used as control.
The acidity values of the samples with sucrose and GS were lower than those of the others. The viscosity value of the sample containing honey and stored for 15 days was the lowest. When honey together with sucrose (1/1) was added to the ice cream mixture, the viscosity increased. On the other hand, using honey increased the fat destabilization value. The overrun ratio of the sample with sucrose was the highest. The lowest melting ratio was determined in samples containing GS at the beginning of storage period. The melting ratios of the ice creams slightly increased during 15 days of the storage. The highest glucose and fructose amounts were observed in the samples made with honey. Panellists preferred the ice cream samples with sucrose  +  GS compared to control and the other samples.

PRACTICAL APPLICATIONS

Due to increasing consumer demands for low calorie foods, products made with alternative sweeteners have became more popular recently. Changing attitudes in sucrose consumption have heightened because of its causing effect to diabetes and obesity. Therefore there is a need for evaluating the alternative sweeteners. Although there were many studies about ice cream in the literature, there are few studies on using different sugars in ice cream production.     

The effects of copper and high sugar concentrations on growth, fermentation efficiency and volatile acidity production of different commercial wine yeast strains

The effect of high sugar concentrations or the presence of copper residues on fermentation efficiency and volatile acid (VA) production were examined for selected commercial wine yeast strains. Fermentation rate as measured by accumulated mass loss appeared to be least affected by high sugar concentrations during the first few days of fermentation for strains VIN13, WE14, N96 and RJ11. It was, however, only fermentations using VIN13, WE372, N96 and L2056 that contained less than 11 g/L fructose after 21 days. VIN13 and RJ11 produced the lowest VA in the 21^o, 25^o and 28^oBrix musts. Fermentation efficiency of six strains was also studied in must containing 0.25 mM Cu²⁺. Results indicated that strains NT50, Collection Cépage Cabernet (CC) and D80 were not significantly affected, whereas VIN13, NT112 and RJ11 contained significantly more glucose and fructose after fermentation in the must containing copper. Copper addition also increased VA production, with strains RJ11 and NT50 being the most affected.     

Quality changes in fresh-cut Fuji apple as affected by ripeness stage, antibrowning agents, and storage atmosphere

ABSTRACT:  The effect of ripening state, modified atmosphere, and the use of antibrowning agents was investigated in an attempt to determine optimum ripeness and processing conditions for extending the shelf-life of fresh-cut Fuji apple. Apples were classified in 3 groups: mature-green, partially ripe, and ripe; after peeling and slicing, fruits were treated with 1% (w/v) N -acetylcysteine, or 1% (w/v) ascorbic acid (control), and then packed into polypropylene trays with air or a gas mixture (2.5% O₂+ 7% CO₂+ 90.5% N₂) and sealed. Trays containing the apple slices were stored in darkness at 4 °C ± 1 °C and analyzed periodically during 43 d. Changes in atmosphere composition, color, and firmness were examined. Partially ripe apples, based on their lower ethanol production and maintenance of their original color and firmness, were the most suitable to prepare the fresh-cut commodities. A postcutting dip in 1% (w/v) N -acetylcysteine was the most effective treatment to prevent cut surface browning and preserve the initial appearance of Fuji apple slices during more than 1 mo at 4 °C. Low O₂ and elevated CO₂ (2.5% O₂+ 7% CO₂) atmosphere extended the shelf life of apple slices because of a significant inhibition of ethylene production.     

高效液相色谱法分析大豆和大豆低聚糖浆中糖的组成与含量

采用高效液相色谱法(HPLC)对大豆种子及市售的大豆低聚糖浆中的可溶糖进行了分析,并利用α-半乳糖苷酶酶解大豆低聚糖浆及结合HPLC分析来推测大豆低聚糖浆的糖组成。HPLC分析条件为:Sugar-D色谱柱,75%乙腈为流动相,柱温40℃,流速为1.0ml/min,示差折光检测器。Sugar-D色谱柱的分离效果好,基线稳定,相对标准偏差1.0%～2.0%,标准回收率96.7%～100.7%。分析结果表明大豆种子和市售的大豆低聚糖浆中均含有果糖、蔗糖、蜜二糖、棉子糖、水苏糖以及二种保留时间介于蔗糖与蜜二糖之间的未知成分,而大豆低聚糖浆中还含有葡萄糖(半乳糖)和甘露三糖;大豆种子中主要含有蔗糖和水苏糖,而大豆低聚糖浆中含有较多的蔗糖、果糖、水苏糖和葡萄糖(半乳糖),功能性低聚糖主要为水苏糖和甘露三糖。     

Influence of oxygen concentration and temperature on respiratory characteristics of fresh-cut green onion

The characteristics of the respiration rates in precut green onion, as influenced by oxygen levels and temperature, were examined to provide design factors for modified atmosphere packaging (MAP). Fresh-cut green onions ( Allium fistulosum L.) were prepared and sealed, with and without a CO₂ absorbent, in gas-tight glass containers that had initially been purged with air or a gas mixture (O₂ 9%/N₂ balance). The containers were stored at different temperatures (0, 10, 20 °C). At 10 °C, the maximum O₂ uptake rate (V_m) and the O₂ concentration at half-maximum (K_m) uptake rate were 30.95 mL kg⁻¹ h⁻¹ and 1.63%, respectively. Regardless of temperature, the lower O₂ limit was estimated to be about 1.0% O₂ on the basis of respiratory quotient (RQ) increase. Respiration of cut green onion was dependent on O₂ concentration as well as temperature, as shown by applying the Michaelis–Menten type model and the Arrhenius equation. However, the presence of CO₂ had little effect on O₂ uptake of cut green onion at relatively high O₂ concentrations (≤20%).