Reduction of non-digestible oligosaccharides in horse gram and green gram flours using crude α-galactosidase from Streptomyces griseoloalbus

The effectiveness of using crude extracellular α-galactosidase from Streptomyces griseoloalbus for the treatment of horse gram and green gram flours was investigated by comparing with traditional treatments such as soaking and cooking. The enzymatic treatment was most effective and the raffinose content in horse gram flour was reduced by 97.5% and stachyose content by 93.2%. The reduction in the raffinose content of green gram flour was 96.3% and that for stachyose was 91.8%. The information obtained from the present investigation is advantageous for the large-scale production of horse gram flour and green gram flour free of flatulence-causing oligosaccharides.     

Effect of compressed fluids treatment on the activity,stability and enzymatic reaction performance of β-galactosidase

The present work investigates, as a first step, the influences of pressure, exposure time and depressurisation rate on the β-galactosidase activity of permeabilized cells of Kluyveromyces marxianus CCT 7082 submitted to treatment with compressed carbon dioxide, propane and n-butane. In general, results showed that the enzyme activity changes significantly, depending on the experimental conditions investigated, allowing the selection of proper operating conditions for advantageous application of this biocatalyst in hydrolysis reactions. Further, the stability of the enzyme, after high-pressure pre-treatment, was also experimentally monitored, and the results demonstrated that the activities of this biocatalyst were always higher than those of the non-treated one. Finally, evaluation of synthesis of galactooligosaccharides (GOS), using β-galactosidase without treatment and after treatment in compressed fluids, was carried out. Results indicated promising possibilities since the use of n-butane-pre-treated enzyme led to very satisfactory reaction conversions and selectivity.     

Reduction of α-galactoside content in red gram (Cajanus cajan L.) upon germination followed by heat treatment

BACKGROUND: Red gram (Cajanus cajan L.) is an important crop for human and animal nutrition. However, raffinose family oligosaccharides present in red gram seed hinder its consumption as it is not digested by normal human carbohydrases and is further fermented by intestinal microflora, which induces flatulence. In order to make the grain legume more amenable for human consumption, we have tried to shed some light on the effect of germination followed by heat treatment methods such as autoclaving, cooking and pressure cooking on the raffinose family of sugars. These techniques, however, are primary prerequisites before consumption of the gram. RESULTS: The percent removal of raffinose, stachyose and verbascose after germinating red gram seeds for 8 h followed by autoclaving was 65.6%, 58.9% and 65.3% respectively; and after cooking was 61.6%, 69.2% and 72.5%. Germinating for 16 h followed by autoclaving led to a mean decrease of 53.3% for raffinose, 60.3% for stachyose and 62.3% for verbascose. Germination of red gram seeds for 16 h followed by cooking led to a mean decrease of 71.7% for raffinose, 76.2% for stachyose and 74.0% for verbascose, respectively. The results for the percent removal of raffinose, stachyose and verbascose after germination of red gram seeds for 16 h followed by pressure cooking was 68.3%, 73.3% and 68.2% respectively. CONCLUSION: This study demonstrates that local methods of processing reduce raffinose family oligosaccharides in red gram. The technique of germinating the seeds for 16 h followed by autoclaving, cooking and pressure cooking for the reduction of raffinose family oligosaccharides is a promising solution to overcome flatulence and increase the overall acceptance of red gram among general populace. Copyright © 2011 Society of Chemical Industry     

Effect of gamma radiation on levels of α-tocopherol in red meats and turkey

The effect of low dose ionizing radiation on free α-tocopherol levels in beef, pork and lamb longissimus dorsi muscle and on turkey leg and breast muscle were determined. The samples were irradiated in air with a ¹³⁷Cs source at eight dose levels between 0 and 9.4 kGy at 5 °C. Irradiation resulted in a significant decrease in α-tocopherol levels in all of the meats studied. There were no statistically significant differences in the rate of loss of tocopherol due to species, with the exception of turkey breast. The rate of loss of tocopherol in turkey breast tissue was greater than the other meats. The information obtained in this study may be of use for ‘chemiclearance’ purposes since the relative effects due to species variation were examined.     

Effect of high-pressure treatment on denaturation of bovine β-lactoglobulin and α-lactalbumin

The effect of high-pressure treatment on denaturation of β-lactoglobulin and α-lactalbumin in skimmed milk, whey, and phosphate buffer was studied over a pressure range of 450–700 MPa at 20 °C. The degree of protein denaturation was measured by the loss of reactivity with their specific antibodies using radial immunodiffusion. The denaturation of β-lactoglobulin increased with the increase of pressure and holding time. Denaturation rate constants of β-lactoglobulin were higher when the protein was treated in skimmed milk than in whey, and in both media higher than in buffer, indicating that the stability of the protein depends on the treatment media. α-Lactalbumin is much more baroresistant than β-lactoglobulin as a low level of denaturation was obtained at all treatments assayed. Denaturation of β-lactoglobulin in the three media was found to follow a reaction order of n = 1.5. A linear relationship was obtained between the logarithm of the rate constants and pressure over the pressure range studied. Activation volumes obtained for the protein treated in milk, whey, and buffer were −17.7 ± 0.5, −24.8 ± 0.4, and −18.9 ± 0.8 mL/mol, respectively, which indicate that under pressure, reactions of volume decrease of β-lactoglobulin are favoured. Kinetic parameters obtained in this work allow calculating the pressure-induced denaturation of β-lactoglobulin on the basis of pressure and holding times applied.     

Impact of selected factors – Cultivar,storage, cooking and baking on the content of anthocyanins in coloured-flesh potatoes

The impact of selected factors – cultivar, storage, cooking and baking on the content of total anthocyanins (TAC) in coloured-flesh potato cultivars has been studied. TAC ranged from 248.5 to 2257.8 mg kg⁻¹ dry matter (DM). TAC difference between cultivars was statistically significant. Cold storage (4 °C) influenced TAC differentially. In the Violette and Highland Burgundy Red cultivars TAC increased by 18.5% and 12.1% respectively, and in the Valfi cultivar it decreased by 33.9%. Baking increased TAC 3.34 times whereas cooking in boiled water increased it 4.22 times. Correlation between antioxidant activity (AOA) and TAC (r² = 0.659) has been found. The Violette, Vitelotte and Highland Burgundy Red cultivars with the highest TAC showed high AOA and the Shetland Black cultivar and the cultivars Salad Blue and Blue Congo with a “marbled” texture showed the lowest TAC and AOA. Individual anthocyanidins are fingerprints of colour-fleshed potato cultivars.     

Effect of tocopherols,tocotrienols, β-carotene,and chlorophyll on the photo-oxidative stability of red palm oil

Effect of tocols, β-carotene, and chlorophyll on photo-oxidative stability of red palm oil (RPO) were studied. Model systems of triacylglycerols+tocols, triacylglycerols+β-carotene, triacylglycerols +tocols+β-carotene, and triacylglycerols+tocols+β-carotene+chlorophyll were exposed to fluorescent light at intensities of 5,000, 10,000, and 15,000 lux for 7 h at 30±2°C. Changes in concentrations of tocopherols, tocotrienols, β-carotene, chlorophyll, and peroxide values were evaluated every hour. Light intensity accelerated degradation of tocols in the triacylglycerols+tocols system and β-carotene in the triacylglycerols+β-carotene system. Gamma-tocotrienol showed the highest degradation rate and β-carotene was the most sensitive compound to changes in light intensity, indicated by the lowest light intensity coefficient (z_i) value. The presence of tocols and β-carotene together showed protective effects for the photo-oxidative stability of RPO. The presence of chlorophyll increased the rate of photo-oxidation at high light intensities. Interactions between tocols and β-carotene contributed to the photo-oxidative stability of RPO.     

Effect of prolonged heat treatment from 48 °C to 63 °C on toughness, cooking loss and color of pork

The effect of low temperature long time (LTLT) heat treatment at 48 °C, 53 °C, 58 °C, and 63 °C for T(c) (time to reach a core temperature equal to the water bath), T(c)+5h holding time, and T(c)+17h holding time was studied in Longissimus dorsi and Semitendinosus muscles from slaughter pigs and sows. Meat toughness (Warner-Bratzler Shear Force), cooking loss and color (Minolta L*a*b*-values) was measured and in the cooking loss the amount of heat-soluble collagen and activity of cathepsin B+L was determined. Decreasing shear force and increasing cooking loss during LTLT treatment was observed between 53 °C and 58 °C. Furthermore, increasing temperature from 53 °C to 58 °C and increasing time from T(c) to T(c)+17h increased the solubility of collagen. Residual activity of cathepsin B+L in LTLT treated pork was mainly affected by temperature, showing the highest activity at 58 °C and 63 °C.     

Effect of Sicilian pasture feeding management on content of α-tocopherol and β-carotene in cow milk

This study was performed to evaluate α-tocopherol and β-carotene contents of pasture milk under ordinary Sicilian farming conditions. Fourteen dairy farms were allocated into 2 balanced groups on the basis of cultivated (CULT) or spontaneous (SPO) pasture type feeding. Bulk milk per farm was collected 4 times from February through April at 3-wk intervals. Pasture botanical and diet composition, diet nutritional quality, milk yield and composition were estimated each time. Pasture intake levels were calculated based on feed analyses, hay and concentrate amounts fed, and milk yield and chemical composition. According to pasture intake, the farms were split into low pasture intake (LPI; <29.5% of dry matter) and high pasture intake (HPI; >29.5% of dry matter) groups. Milk samples per farm were analyzed for α-tocopherol and β-carotene contents by HPLC. The SPO group had higher levels of α-tocopherol and β-carotene in milk (0.7 and 0.3 mg/L, respectively) and milk fat (19.0 and 7.5 mg/kg fat, respectively) compared with the CULT group in milk (0.5 and 0.2 mg/L, respectively) and milk fat (14.6 and 4.9 mg/kg, respectively). High pasture intake compared with LPI increased α-tocopherol in milk fat (18.0 and 16.0 mg/kg of fat, respectively). However, only in the SPO (not in CULT), HPI compared with LPI increased milk α-tocopherol (0.8 vs. 0.6 mg/L, respectively), milk β-carotene (0.3 vs. 0.2 mg/L, respectively), and milk fat β-carotene (8.4 vs. 6.6 mg/kg, respectively). Results may be related to the different botanical composition of the respective pasture types and pasture intake. Spontaneous pasture compared with CULT contained a higher mass proportion of Asteraceae, Fabaceae, Cruciferae, Euphorbiaceae, and Malvaceae plants. Milk and milk fat α-tocopherol levels were higher on test-days (TD)-1, TD-2, and TD-4 compared with TD-3. For HPI farms, milk fat β-carotene content was higher on the first 2 TD compared with the last 2 TD. These differences could be related to plant biological stage. On Sicilian dairy farms, the highest milk α-tocopherol and β-carotene contents may be obtained feeding high levels of SPO pasture in the spring.     

Effect of water content,temperature and storage on the glass transition,moisture sorption characteristics and stickiness of β‐casein 1

Moisture sorption isotherms at +4 °C and +22.5 °C were obtained for β‐casein after isolation and after 9 months of storage at ‐29 °C and +22.5 °C. Glass transition state diagrams (T_g vs. moisture) were determined for β‐casein after storage. The results showed that effects of storage temperature on moisture sorption isotherms were varied; however, at any a_w differences in moisture content were small (< 0.03g H₂O/g solids at high a_w). β‐casein stored at ‐29°C had lower m_o and T_g values than that of β‐casein stored at +22.5°C. The glass transition temperatures for β‐casein were above room temperature, even at a_w = 0.76. Onset of stickiness occurred above a_w = 0.76.     

The effect of dietary supplementation of vitamins C and E on the α-tocopherol content of muscles, liver and kidney, on the stability of lipids, and on certain meat quality parameters of the longissimus dorsi of rabbits

The trial was carried out to investigate the effects of adding to the diet of rabbits vitamin E (40; 300; 500 ppm) and C (0; 500 ppm), on vitamin E deposition in the muscles and organs, on the oxidative stability of muscular lipids, and on various meat quality characteristics. The α-tocopherol content in muscles and organs was roughly doubled by feeding the highest levels of vitamin E; it was also increased by giving 500 ppm of vitamin C, but only in those muscles of rabbits receiving 40 ppm of vitamin E. The α-tocopherol content in tissues was negatively correlated with TBARS values of the longissimus dorsi (LD) at days 6 and 8 post mortem (p.m.). Five hundred parts per million (ppm) of vitamin C increased lipid stability of the LD at both 6 and 8 days p.m., though its effect was significant only with 40 ppm of vitamin E. Moreover, 500 ppm of vitamin C resulted in the lowest L(*) and highest pH values at all p.m. times, when the dietary vitamin E was equal to 40 ppm, and in the highest L(*) and lowest pH values when the vitamin E was equal to 300 ppm. Conversely, weight losses of the LD were the lowest, at days 6 and 8 p.m., in the group fed the highest levels of both vitamins.     

Effect of acid and base treatments on structural,rheological, and antioxidant properties of α-zein

Five pH levels were experimented to study their effect on zein structural, rheological, and antioxidant properties. Structural changes, including secondary structures, surface charge, molecular weight, particle size distribution, and morphology were evaluated using a spectrum of instruments. Zein rheology, including the viscosity and viscoelastic property, was examined by a rheometer. The antioxidant efficacy was determined by measuring the scavenging activity of 1,1-diphenyl-2-picrylhydrazyl free radical and the reducing power of 1,10-phenanthroline-iron with a spectrophotometer. Results indicated that under proper acidic or basic conditions, zein structures, rheological behaviour, and antioxidant properties changed significantly. Decreased contents for α-helix, β-sheet, and β-turn were detected by the Fourier transform infrared spectroscopy for zein samples at acidic and basic conditions comparing to those in a near neutral condition, which were attributed to the deamidation of glutamine to glutamic acid/glutamate in zein. However, no obvious zein fragmentation or oligomerization was detected by the sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The mild deamidation without fragmentation led to a decreased viscosity and an improved antioxidant property of zein. Modified rheological behaviour and enhanced antioxidant properties resulting from a pH treatment may facilitate novel application development of zein in food and pharmaceutical industries.     

Effect of high-pressure treatment and a bacteriocin-producing lactic culture on the proteolysis, texture, and taste of Hispánico cheese

The effects of high-pressure treatment, by itself or in combination with a bacteriocin-producing culture added to milk, on the proteolysis, texture, and taste of Hispánico cheese were investigated. Two vats of cheese were manufactured from a mixture of cow and ewe milk. Milk in one vat was inoculated with 0.5% Lactococcus lactis ssp. lactis INIA 415, a nisin Z and lacticin 481 producer; 0.5% L. lactis ssp. lactis INIA 415-2, a bacteriocin-nonproducing mutant; and 2% of a commercial Streptococcus thermophilus culture. Milk in the other vat was inoculated with 1% L. lactis ssp. lactis INIA 415-2 and 2% S. thermophilus culture. After ripening for 15 d at 12°C, half of the cheeses from each vat were treated at 400 MPa for 5 min at 10°C. Ripening of high-pressure-treated and untreated cheeses continued at 12°C until d 50. High-pressure treatment of cheese made from milk without the bacteriocin producer accelerated casein degradation and increased the free AA content, but it did not significantly influence the taste quality or taste intensity of the cheese. Addition of the bacteriocin producer to milk lowered the ratio of hydrophobic peptides to hydrophilic peptides, increased the free AA content, and enhanced the taste intensity. The combination of milk inoculation with the bacteriocin producer and high-pressure treatment of the cheese resulted in higher levels of both hydrophobic and hydrophilic peptides but had no significant effect on the free AA content, taste quality, or taste intensity.     

Effect of ascorbyl palmitate on the preservation of α-tocopherol in sunflower oil,alone and with herbs and spices

Ascorbyl palmitate (AP) (200 ppm) preserved α-tocopherol in sunflower oil at 95°C and delayed the onset of rancidity. Both effects increased with AP concentration (r² = 0.96 and 0.97 respectively) but levelled off near ∼700 ppm. The improved anti-rancidity effect was due to the increased preservation (P<0.01). Synergism was observed for both effects for AP combined with sage, turmeric, oregano and marjoram. Clove and thyme gave a smaller synergistic effect whereas basil inhibited. Neither bay nor cumin had any effect. Both the preservative (PF_p) and anti-rancidity effects (PF_r) were directly related to the thyme concentration (0–2000 ppm). Again, the decreased rancidity was due to the increased preservation (P<0.01). The optimum AP concentration (0–1000 ppm) was around 250 ppm (P<0.01) with thyme present (at 500 ppm) (r²=0.99). The increased delay in rancidity was due to the improved preservation of α-tocopherol (r=1, r² = 0.99, P<0.01). Both the logarithm of the induction time and the preservative effect for the mixture of thyme and AP was directly related to the temperature (80–105°C). The mode of action of AP is also discussed.     

Effect of ultrasound treatment on the wet heating Maillard reaction between β-conglycinin and maltodextrin and on the emulsifying properties of conjugates

Soy β-conglycinin (7S) was grafted with maltodextrin (MD) by combined ultrasound treatment and wet heating Maillard reaction in this work. The physicochemical and emulsifying properties of 7S–MDH (classical wet heating) and 7S–MDUH (ultrasound-assisted wet heating grafting) have been investigated. Ultrasound treatment could speed up the conjugation process and obtain a protein–polysaccharide conjugate that exhibits superior functionality compared with the one obtained simply by wet heat treatment. The degree of grafting of 32.73 % was obtained in 30 min by ultrasound-assisted wet heating , whereas classical wet heating required 60 min. SDS-PAGE analysis indicated that 7S globulin had become complex with MD to form conjugates of higher molecular weight. Reduction in the contents of lysine and arginine during the graft reaction indicated that these two amino acid residues had the covalent linkage between 7S and MD. The results of secondary structure showed that grafted 7S had decreased α-helix level and increased β-sheet and unordered coil levels. In addition, ultrasound-assisted treatment significantly changes in surface hydrophobicity (H ₀), emulsifying activity index and emulsifying stability index of 7S (p < 0.05). Moreover, the emulsions of 7S–MDUH were stable under unfavorable conditions, such as extreme pH, ionic strength and heat treatment temperature, which is mainly due to changes in surface hydrophobicity (H ₀) and secondary structure, resulting in a reduction in protein molecular steric hindrance in an increase in molecular flexibility. This study demonstrated that combined ultrasound treatment and wet heating Maillard reaction could potentially be applied as a method to prepare 7S–MD conjugates.     

Effect of fermentation on content,molecule weight distribution and viscosity of β-glucans in oat sourdough

This study investigated the effect of fermentation on the physicochemical properties of β-glucans in oat sourdough. Sourdoughs were produced from oat using homo-fermentative lactic acid bacteria, Lactobacillus plantarum 22134. The contents of total β-glucan and soluble β-glucan, the molecular weight (MW) of β-glucan and the viscosity of the extracted β-glucans were determined at 0, 4, 8, 10 and 12 h of fermentation. The total β-glucan content decreased from 4.89% to 4.23% after 12 h of fermentation. The soluble β-glucan concentration increased from 1.89% to 2.18% and then decreased to 1.97% after 8 h of fermentation. The content of β-glucans with MW > 10⁵ decreased from 0 to 4 h of fermentation, followed by an increase and then a decrease after 8 h. The oat sourdough fermented for 8 h had high viscosity, which could be more beneficial for health and bread texture quality, especially for gluten-free breads.     

Effect of organic calcium salts–inulin systems on hydration and thermal properties of wheat flour

The aim of this work was to study the effect of calcium acid salts–inulin systems on hydration and thermal properties of wheat flour dough. Wheat flour was enriched with calcium lactate (CaLa₂) or calcium citrate (Ca₃Ci₂) (1080–2520 ppm Ca) and inulin (In) (1%–13%, w/w flour basis). Water absorption (W_abs), moisture content (M_cont), water activity (a_w) and relaxation time (λ) of dough were analyzed. Pasting properties during heating–cooling process were studied: peak viscosity (PV), breakdown (BD), final viscosity (FV) and setback 1(SB1) were determined. Temperatures (T_pI, T_pII) and enthalpy (?H_gel) of gelatinization of dough were analyzed by DSC. Samples with Ca and In presented lower W_abs than control sample with an In² dependence, with slight difference between both surface responses. More time for dough development (t_d) was necessary with Ca₃Ci₂ than with CaLa₂, being t_d independent of calcium content at In level (≥ 6.5%). Dough with Ca₃Ci₂ was more stable with less degree of softening than CaLa₂-dough, due to the protein stabilizing effect of citrate ion (Hofmeister series) with a maximum at 6.5% In. M_cont and λ decreased with the increase of In, independently of calcium. Hydration properties directly influenced pasting parameters. The increase in In content decreased viscosity (PV, FV) without affecting BD. SB1 behavior suggests the formation of pastes with low and high stability with CaLa₂ and Ca₃Ci₂, respectively. Gelatinization degree decreased (40%) and retarded (?T = 10 °C) at high levels of both ingredients. CaLa₂ had more influence in hydration and thermal properties of wheat flour–inulin blends, enhancing a high degree of inhibition of gelatinization and leading to pastes with low viscosity after cooling. This behavior was influenced by the presence of inulin.