Effect of water activity on sugar crystallization and β-carotene stability of freeze-dried mango powder

Storage water activity (a_w) affects the stability of freeze-dried food. The sugar crystallization and storage stability of β-carotene in freeze-dried mango powder was investigated following storage under various relative vapor pressures (11.3-80.9%). Sugar crystallization was revealed by the loss of sorbed water in the water sorption experiment. However, the sorption isotherms showed unclear divergence between the experimental and predicted values. X-ray powder diffraction and scanning electron microscopy were used to confirm the crystallization. The results showed that increased a_w resulted in higher sugar crystallization. The loss of β-carotene was monitored by high-performance liquid chromatography with a diode-array detector and fitted to a first-order reaction. The rate constant decreased as a_w increased up to 0.43, due to the collapse of the mango powder. An increase in the rate constant above this value of a_w coincided with pronounced sugar crystallization. Choosing the appropriate value of a_w for storage can prevent sugar crystallization and enhance β-carotene stability in freeze-dried fruit powder.     

Effect of barley β-glucan on water redistribution and thermal properties of dough

The effect of adding barley (Hordeum vulgare L.) β-glucan (BBG) to dough on the water redistribution and the thermal properties of dough was studied by TGA and DSC. Combined with LF-NMR to analyse the competition and redistribution mechanism of water at the ¹H level. The mass loss of the dough measured by TGA was reduced by an average of 2.11% with BBG added. BBG increased the water retention of the dough, delayed the water loss process. The LF-NMR results showed that at the same water absorption the T21 of the 3% BBG dough was longer while its T22 was shorter than those of the control. BBG has different effects on the different states of water in the dough. BBG increased the free sulfhydryl content in dough during heating, while the adverse effects of BBG on the biopolymer reactions, such as disulfide bond, could be partially relieved by regulating water content.     

Degradation kinetics of β-carotene in carrot slices during convective drying

The β-carotene degradation was investigated in carrot (Daucus carota L. cv Nantes) slices during convective drying at three temperatures (45, 55, and 65°C) at an airflow rate of 0.2 m s^–1. Degradation kinetics of β-carotene in carrot slices during convective drying followed a first-order reaction. Drying temperature showed a significant effect on the degradation of β-carotene in carrot slices. The range of the reaction rate constants for β-carotene loses were 0.23 ± 0.08 –0.48 ± 0.04 h^–1. The activation energy of β-carotene degradation is found 33.33 ± 0.05 kJ mol^–1. Half-life time was calculated as 3.02 ± 0.04 h at 45°C, which dropped to 1.43 ± 0.03 h at 65°C.     

Influence of ligand structure and water interactions on the physical properties of β-cyclodextrins complexes

The water sorption and physical properties of freeze-dried β-cyclodextrin (BCD) and 2-hydroxypropyl-β-cyclodextrin (HBCD) were studied. The stability of the inclusion complexes of these cyclodextrins with different hydrophobic ingredients, such as myristic acid and α-terpineol, was investigated as a function of the storage time and water content of the systems. Besides increasing its solubility, BCD ring modification with hydroxypropyl groups conferred amorficity to the dehydrated matrices, and modified the sorption properties and their ability to form hydrates.     

Effect of heating on solid β-carotene

The effect of heating on isomerisation and stability of solid β-carotene was investigated, and the products generated by heating were analysed by a number of analytical techniques, including high-performance liquid chromatography (HPLC), UV/VIS-spectroscopy (UV) and gel permeation chromatography (GPC). For the first time, isomerisation of cis- to all-trans-isomer was demonstrated in partly melted solid β-carotene when β-carotene was heated at 90 and 140 °C. Only a few high molecular weight components were detected by GPC when β-carotene was heated in a nitrogen environment. In contrast, more high molecular weight polymers, as well as low molecular fragments, were produced when β-carotene was heated and exposed to air, suggesting that polymerisation was one of the dominant side-reactions of β-carotene change, in addition to degradation.     

Effect of sea water on water absorption and flexural properties of?wood-polypropylene composites

The effects of Caspian Sea and Persian Gulf waters on the physical and mechanical properties of wood- polypropylene composites were studied. For physical tests, the composites were immersed in Caspian Sea, Persian Gulf and distilled water and long term water absorption was determined. For mechanical tests, the prepared composites were immersed in Caspian Sea, Persian Gulf and distilled water for 7 or 30 days, removed from water and their flexural properties were measured. The composites immersed in Persian Gulf water exhibited higher water absorption and lower flexural properties than those immersed in Caspian Sea and distilled water, respectively. At higher sawdust content, the type of water is more effective on increasing water absorption and decreasing flexural properties.     

Water dispersibility of the β-carotene source and its effect on the physical,thermal, and in vitro release properties of an inclusion complex

There is a need to understand the effect of in vitro digestion on the release of β-carotene (BC) from inclusion complexes (IC) prepared with water-dispersible (WDBC) or hexane-soluble (HSBC) sources. IC were prepared by co-precipitating WDBC or HSBC with β-cyclodextrin and characterised using imaging, spectral (FTIR) and thermal techniques. Two solvent systems (absolute ethanol, AE and 4:3 ethanol–hexane, EH) were employed to compare extractability of BC during simulated co-digestion with rice as food matrix. WDBC-IC had greater yield (89% vs. 44%) but lower encapsulation efficiency (30% vs. 89%) than HSBC-IC. Imaging, FTIR and thermal data confirm inclusion complex formation. In vitro WDBC release extracted with AE decreased uniformly and was unaffected by rice, whereas HSBC extracted with EH exhibited gradual release towards intestinal digestion but decreased with rice. Fabricated microcapsules with suitable forms of BC may be applied for food fortification purposes.     

Effect of hydroxypropyl β-cyclodextrin on physical properties and transition parameters of amylose–lipid complexes of native and acetylated starches

The effect of hydroxpropyl β-cyclodextrin (HPβ-CD) on physical properties and digestibility of wheat, potato, waxy maize and high-amylose maize starches before and after acetylation was studied. Effect of HPβ-CD on amylose–lipid complexes in native and acetylated potato starches synthesized using α-lysophosphatidylcholine was also studied. Acetylation increased swelling factor, amylose leaching, peak viscosity and susceptibility to α-amylase hydrolysis, but decreased gelatinization temperature and enthalpy and gel hardness in all starches. HPβ-CD markedly increased swelling factor and amylose leaching in native and acetylated wheat starches but had little or no impact on other starches. Wheat starch gelatinization enthalpy decreased in the presence of HPβ-CD but gelatinization temperature of all the starches was slightly increased. HPβ-CD had no influence on enzymatic hydrolysis. Melting enthalpy of amylose–lipid complex in both native and acetylated wheat starches was decreased by HPβ-CD. Acetylation also decreased the melting enthalpy of amylose–lipid complex in wheat starch. Similar trend of thermal transitions was observed in the presence of HPβ-CD for the amylose–lipid complexes synthesized in potato starch. Acetylation reduces the complex formation ability of the amylose polymer. Similar to gelatinization, acetylation widened the melting temperature range of amylose–lipid complexes while shifting it to a lower temperature. Higher swelling and amylose leaching, and decreased gelatinization temperature and enthalpy resulting from acetylation of wheat starch is consistent with its influence on starch hydration. Similar effects resulting from the inclusion of HPβ-CD were consistent with the disruption of amylose–lipid complex by HPβ-CD which promotes granular hydration.     

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.     

Degradation and isomerization of chlorophyll a and β-carotene as affected by various heating and illumination treatments

The degradation and isomerization of β-carotene and chlorophyll a as affected by oven-heating, reflux-heating, iodine-catalysed illumination, and non-iodine-catalysed illumination, were studied. Results showed that the degradations of both total β-carotene and chlorophyll a may fit the first-order model under either heating or illumination treatment. 13-cis-β-Carotene and 13,15-di-cis-β-carotene were the major cis isomers of β-carotene formed during oven heating, while 13-cis-β-carotene was favoured during reflux heating. For illumination with or without iodine as catalyst, 13,15-di-cis-β-carotene was the major cis isomer of β-carotene formed. The formation of 13,15-di-cis-β-carotene may be due to conversion of either 13-cis- or 15-cis-β-carotene. No epimerization of chlorophyll a was observed as a result of illumination.     

Effect of β-cyclodextrin on physical properties of nanocapsules manufactured by emulsion–diffusion method

This study was carried out to investigate the effect of β-cyclodextrin (β-CD) as a cryoprotectant on the eugenol encapsulated nanocapsules. Nanocapsules (NCs) were prepared by emulsion–diffusion method and frozen at various temperatures (−30 °C to −10 °C). Physical stability of the NCs was determined by particle size analysis and morphological observation using scanning or transmission electron microscopy before and after freezing or freeze-drying process. Freeze-thawed and freeze-dried NCs without β-CD were remarkably aggregated. The particle size of NCs without β-CD was significantly increased as decreasing freezing temperature. On the contrary, NCs with β-CD were slightly increased in the range of 370–400 nm. Significant particle aggregation was not shown at NCs with β-CD at all freezing temperatures. In this study, β-CD could was effective as a cryoprotectant to maintain physical stability of NCs after freezing or freeze-drying. β-CD could be useful to protect NCs from freezing stress.     

Effect of chitosan molecular weight on the stability and rheological properties of β-carotene emulsions stabilized by soybean soluble polysaccharides

In this study, β-carotene emulsions were prepared using a two-stage homogenization process and adsorption of chitosan to anionic droplets coated with soybean soluble polysaccharides (SSPS). Effects of the molecular weights of chitosan on the stability and rheological properties of β-carotene emulsions were investigated. Results demonstrated that the ζ-potential, particle size and rheological properties of emulsions were greatly dependent on the chitosan molecular weight. It was found that the particle size of SSPS-stabilized emulsions increased with the rise of chitosan molecular weight at higher chitosan concentrations (>0.2 wt%). Chitosan molecular weight had a significant impact on the heat and light stability of β-carotene in emulsions. SSPS-stabilized emulsion with the adsorption of medium molecular weight-chitosan (MM-chitosan) was more stable than those with the adsorption of low and high molecular weight-chitosan (LM-chitosan and HM-chitosan). Dynamic oscillatory shear tests indicated that the viscoelasticity could be enhanced by the adsorption of higher molecular weight of chitosan onto the SSPS-coated droplet surfaces.     

Effect of γ-irradiation on physical quality attributes and identification properties of different sauces

Gamma-irradiated (0, 1, and 10 kGy) ketchup (KTP), barbeque sauce (BBQ), and sweet chili sauce (SWC) were identified using photostimulated-luminescence (PSL) and thermoluminescence (TL) analysis and characterized for physical properties like Brix, consistency, and color. PSL-based screening showed negative results for all nonirradiated samples, while intermediated results were found for irradiated samples. Routine density separation method for mineral extraction provided better TL results; however, alkaline and acid hydrolysis could ease the process with acceptable results. A slight decrease in consistency of all the samples was observed. Brix of KTP remained unchanged, while increase of same was obvious in BBQ and SWC following irradiation. The Hunter L* value of the γ-irradiated sauces decreased except SWC samples, and the a* and b* values showed a general increase compared to the non-irradiated samples. The studied methods have potential to successfully identify and characterize the irradiated sauces for technical and regulatory requirements.     

Improved incorporation and stabilisation of β-carotene in hydrocolloids using glycerol

In this paper, a novel method for the incorporation of the antioxidant β-carotene in hydrocolloid matrices is presented, which consists on the use of glycerol as the vehicle for incorporation. This alcohol has been observed to greatly photostabilise the carotenoid molecule within the hydrocolloid matrices without greatly affecting the mechanical properties of the materials. The UV stability of β-carotene in the different hydrocolloid films developed (including starch, soy protein, whey protein concentrate, gelatin and zein) has been studied using UV/visible spectrophotometry, colorimetry and Raman spectroscopy. Raman images of the materials were also generated in order to ascertain the dispersion of the antioxidant within the hydrocolloid materials and it was observed that β-carotene was partially agglomerated in certain areas of the film, fact that could also contribute to enhance the stability of the bioactive molecule.     

Effect of vitamin E supplementation on α-tocopherol and β-carotene concentrations in tissues from pasture- and grain-fed cattle

The effects of dietary vitamin E supplementation of grain-fed cattle on lipid oxidation and meat colour have been extensively investigated, but little attention has been given to pasture-fed cattle where meat is likely to contain naturally high amounts of α-tocopherol and carotenoids. In the work described, we evaluated the effects of pasture-feeding alone and with vitamin E supplementation on tissue levels of anti-oxidants and compared the findings with those obtained for grain-fed cattle with and without supplementation. Sorghum was the major component of the grained-based ration. α-Tocopherol concentrations in plasma, muscle and fat tissues of pasture-fed cattle were not affected by vitamin E supplementation (2500 IU/head/day for 132 days prior to slaughter) while those of grain-fed cattle increased significantly. The α-tocopherol concentrations in the supplemented grain-fed cattle were similar in muscle and liver to pasture-fed animals but were lower in their fat (P<0.05). The major carotenoid present in all tissues studied from pasture-fed was β-carotene and its contents in plasma, liver, fat and muscles were decreased (P<0.05) by supplementation with vitamin E. Carotenoids were essentially absent in grain-fed cattle except for small amounts in liver. The implication of this study for the meat industry is that cattle grazed on good pasture can achieve concentrations of α-tocopherol in muscles and other tissues at least as high as those obtained by supra-nutritional supplementation of grain-fed cattle with vitamin E. However, α-tocopherol supplementation of pasture-fed cattle reduced tissue concentrations of β-carotene, which would reduce carcase fat yellowness and make pasture-fed cattle more acceptable to some Asian markets.     

Effect of pulsed-light processing on the surface and foaming properties of β-lactoglobulin

Pulsed-light processing was used to treat β-lactoglobulin (BLG) solutions. The impact of pulsed light (PL) on the structural properties of this protein was explored through far-UV, CD spectral analysis, size exclusion chromatography, surface hydrophobicity and NMR spectroscopy. Changes on these physicochemical properties were related to surface rheology, surface tension, foam stability and foam capacity of the non-treated and treated BLG to elucidate adsorption mechanism and consequences on foaming capacity. Conformational modification of BLG was related with PL total fluence as important conformational changes increased when total fluence was higher. Consequently, adsorption rate of treated BLG at the air/water interface was faster than native BLG. Additionally, treated BLG formed highly elastic interfaces. This was found to have an impact on the foam stability. Pulsed-light treatment seemed to enhance the overall strength of the interface, resulting in more stable foams.     

Changes in β-carotene bioaccessibility and concentration during processing of carrot puree

The effect of some process and product factors (addition of olive oil, high pressure homogenisation, subsequent thermal or high pressure pasteurisation) on β-carotene bioaccessibility and isomerisation of carrot puree was investigated. High pressure homogenisation could improve β-carotene bioaccessibility by disrupting cells, but only at a pressure higher than 50 MPa. Softening of the cell walls during a subsequent thermal pasteurisation resulted in a further increase in β-carotene bioaccessibility. Unfortunately, the high temperature also induced formation of some undesirable cis-isomers. As cell walls are probably strengthened by high pressure, high pressure pasteurisation could not positively affect the amount of bioaccessible β-carotene. Moreover, the high pressure process induced β-carotene oxidation. A positive effect of olive oil on β-carotene bioaccessibility could only be noticed in combination with a thermal pasteurisation process when β-carotene was solubilised in the oil droplets. Under high pressure however, oil can be crystallised which hinders the solubilisation of β-carotene.     

Degradation of β-carotene with the effects of light and sulfur dioxide may be responsible for the formation of white spot in dried apricots

Light and sulfur-induced degradation of -carotene flushing out of cells with the effect of salivary pectolytic enzymes of bugs belonging to the family of Heteroptera have been shown to be responsible for the formation of white spot in dried apricots affecting the product quality adversely. The effects of light and sulfur dioxide on the degradation of -carotene were studied in the model systems. Light-induced degradation rate of -carotene was higher at shorter wavelengths. Sulfur-induced degradation reaction of -carotene followed a second-order rate law with a rate constant of 1687 M^–1 min^–1.At shorter wavelengths, light energy was mainly responsible for the degradation of -carotene while sulfur dioxide was more effective on -carotene degradation at higher wavelengths.     

Antioxidant and prooxidant activities of β-carotene in accelerated autoxidation and photosensitized model systems

Food Science and Biotechnology - Antioxidant or prooxidant activity of β-carotene was studied in autoxidized or methylene blue photosensitized lard using the depletion of headspace oxygen,...