Physical properties and microstructure of pidan yolk as affected by different divalent and monovalent cations

Changes in physical property and microstructure of pidan yolk were monitored during pickling in the presence of different divalent (CaCl₂, MgCl₂) and monovalent (KCl) cations at different levels (2 and 5 g kg⁻¹) up to 3 weeks, followed by ageing for another 3 weeks. Pidan prepared following the commercial process, in which PbO₂ or ZnCl₂ at a level of 2 g kg⁻¹ was incorporated, was also tested. Hardness, hardening ratio, NaCl content and pH of yolk gradually increased, whereas moisture content, cohesiveness and adhesiveness decreased as the pickling/ageing time increased up to 6 weeks, regardless of cations used. During pickling/ageing, L* and b* values of interior yolk and a* of exterior yolk decreased, while L* and b* values of exterior yolk and a* value of interior yolk increased (P < 0.05). Yolk of pidan treated with PbO₂ at a level of 2 g kg⁻¹ was semisolid with lower hardening ratio, hardness, cohesiveness and adhesiveness, compared with those from other treatments. Those treated with ZnCl₂ or CaCl₂ at a level of 2 g kg⁻¹ yielded higher hardening ratio, hardness and cohesiveness but lower adhesiveness than others. Confocal laser scanning microscope indicated that the greater dehydration and release of lipids took place in pidan yolk during pickling/ageing of 6 weeks.     

Effect of a commercial adjunct culture on organic acid contents of low-fat Feta-type cheese

The effect of a commercial adjunct culture (CR-213, containing Lactococcus lactis subsp. cremoris and Lactococcus lactis susp. lactis and added at the level of 0.6 g kg⁻¹ or 0.9 g kg⁻¹ cheese milk) on the organic acid (OA) content of low-fat Feta-type cheese was studied. Full-fat (∼220 g kg⁻¹) and a low-fat (∼70 g kg⁻¹) cheeses were used as controls. The main OA of all cheeses throughout ripening were lactic, citric and acetic acids. The effect of ripening time was significant (P < 0.05) for all OA but treatments did not affect acetic, succinic and uric acids. Cheeses with lower fat content were found to contain significantly (P < 0.05) more lactic and citric but less butyric acid than the full-fat control. The addition of the adjunct culture had a positive effect on butyric acid, propionic acid and acetoin content. The use of the adjunct culture could enhance the production of OA in low-fat Feta-type cheeses with eventual positive effect on their sensory properties.     

Potential use of antioxidative mungbean protein hydrolysate as an anticancer asiatic acid carrier

This study investigated the potential use of mungbean (Vigna radiata (L.) Wilczek) protein hydrolysate (MPH) prepared from tryptic hydrolysis as an antioxidative hydrolysate and as a carrier for anticancer asiatic acid (AA). The antioxidant capacity of MPH was 0.67 and 0.46 ??mol Trolox equivalent (TE)/mg protein, as measured by oxygen radical absorbance capacity-fluorescein (ORAC_FL) and Trolox equivalent antioxidant capacity (TEAC) assays, respectively. Freeze-drying in lactose excipient reduced the antioxidant capacity of MPH to 0.48 ??mol TE/mg protein in ORAC_FL assay (P < 0.05) but did not alter antioxidant capacity determined by TEAC assay (P ≥ 0.05). The genotoxicity of H₂O₂ (50 ??M, 30 min) on hepatoblastoma HepG2 could be alleviated after HepG2 cells had taken up MPH after H₂O₂ exposure (P < 0.05). Moreover, the inhibition concentration (IC₅₀) of AA in HepG2 was lowered from 58.5 ??g mL^− 1 of AA alone to 38.5 ??g mL^− 1 when AA was freeze-dried with MPH in lactose excipient (P < 0.05). This study suggested that the efficacy of anticancer pentacyclic triterpene AA against hepatoblastoma HepG2 could be increased by co-drying with antioxidative mungbean protein hydrolysate in lactose excipient.     

Solid-state fermentation of apple pomace using Phanerocheate chrysosporium – Liberation and extraction of phenolic antioxidants

Apple pomace is a by-product from the apple processing industry and can be used for the production of value-added phenolic compounds. A study was carried out to understand the changes and liberation of phenolic compounds and improvement in antioxidant activity during solid-state fermentation of apple pomace using Phanerocheate chrysosporium. The solid-state fermentation of apple pomace using P. chrysosporium mobilised the polyphenolic compounds and improved the nutraceutical properties. The polyphenol content in acetone extract increased and the results were statistically significant (P < 0.05) from 4.6 to 16.12 mg GAE/g dry weight during solid-state fermentation. The effect of various solvents, temperature, time and detergents were also investigated for the extraction of polyphenolics by ultrasonication and microwave-assisted extraction methods. The polyphenol content of the extracts was found to be in the range of 5.78–16.12 mg GAE/g DW of samples, depending on the solvent, extraction time and temperature. Antioxidant activities of polyphenol extracts were tested using the 2,2-diphenyl-1-picryhydrazyl (DPPH) radical methods, where the IC₅₀ ranged from 12.24 to 23.42 μg DW sample, depending on the extraction conditions and the antioxidant activities correlated well with the polyphenol concentrations.     

Tungsten permanent chemical modifier with co-injection of Pd(NO3)2 + Mg(NO3)2 for direct determination of Pb in vinegar by graphite furnace atomic absorption spectrometry

A tungsten carbide coating on the integrated platform of a transversely heated graphite atomizer (THGA^®) used together with Pd(NO₃)₂ + Mg(NO₃)₂ as modifier is proposed for the direct determination of lead in vinegar by graphite furnace atomic absorption spectrometry. The optimized heating program (temperature, ramp time, hold time) of atomizer involved drying stage (110 °C, 5 s, 30 s; 130 °C, 5 s, 30 s), pyrolysis stage (1000 °C, 15 s, 30 s), atomization stage (1800 °C, 0 s, 5 s) and clean-out stage (2450 °C, 1 s, 3 s). For 10 μL of vinegar delivered into the atomizer and calibration using working standard solutions (2.5–20.0 μg L⁻¹ Pb) in 0.2% (v/v) HNO₃, analytical curve with good linear correlation (r = 0.9992) was established. The characteristic mass was 40 pg Pb and the lifetime of the tube was around 730 firings. The limit of detection (LOD) was 0.4 μg L⁻¹ and the relative standard deviations (n = 12) were typically <8% for a sample containing 25 μg L⁻¹ Pb. Accuracy of the proposed method was checked after direct analysis of 23 vinegar samples. A paired t-test showed that results were in agreement at 95% confidence level with those obtained for acid-digested vinegar samples. The Pb levels varied from 2.8 to 32.4 μg L⁻¹. Accuracy was also checked by means of addition/recovery tests and recovered values varied from 90% to 110%. Additionally, two certified reference materials were analyzed and results were in agreement with certified values at a 95% confidence level.     

Development of polyclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for sodium saccharin residue in food samples

A sensitive and specific polyclonal antibody (PcAb)-based indirect competitive enzyme-linked immunosorbent assay (icELISA) for sodium saccharin is described. 6-Amino saccharin was coupled to carrier protein for artificial antigen by diazotisation. New Zealand white rabbits were immunised to obtain anti-sodium saccharin PcAb and then icELISA was developed. The assay showed high sensitivity and specificity to sodium saccharin, with the 50% inhibition value (IC₅₀) of 0.243 μg mL⁻¹, workable range (IC₃₀–IC₇₀) of 0.050–12.8 μg mL⁻¹ and limit of detection (LOD, IC₂₀) of 0.021 μg mL⁻¹. The average recoveries of sodium saccharin in spiked food samples were estimated ranging from 70.7% to 98.8%. A statistically significant correlation of results was obtained between this new ELISA and previously established HPLC approaches with the food-relevant sodium saccharin concentration range 0–320 μg mL⁻¹ (R² = 0.9887–0.9975). These results indicated that the established ELISA was a potential and useful analytical tool for rapid determination of sodium saccharin residue in food samples.     

Comparison of sterol composition between Tuber fermentation mycelia and natural fruiting bodies

Truffle, belonging to Tuber genera, is a nutritious and sterol-rich edible fungus, and sterol is a potential health beneficial compound. A comparison of Tuber sterol composition indicates that the total sterol contents in the fermentation mycelia (i.e., 10.5 mg g⁻¹) (n = 3) were approximately 3.2-5.6 times higher than that of the fruiting bodies (p < 0.05) with the addition of soybean flour into the basal fermentation media. Moreover, the phytosterol profile of fermentation mycelia could be significantly improved by adding soybean flour into the fermentation media. After the addition of soybean flour, stigmasterol and β-sitosterol appeared in the fermentation mycelia and the contents of total phytosterols (2279 μg g⁻¹) (n = 3), brassicasterol (943 μg g⁻¹) (n = 3), and campesterol (418 μg g⁻¹) (n = 3) were all increased significantly (p < 0.05). Moreover, the total contents of sterols and phytosterols in the fermentation mycelia cultured in the soybean media were much higher than those in the fruiting bodies (i.e., 1883-3240 and 479-1832 μg g⁻¹, respectively) (n = 3, p < 0.05). This work confirms the potentiality of Tuber fermentation mycelia as the alternative resource for its fruiting bodies from the viewpoint of sterols production.     

Tyrosinase inhibitory activity of native plants from central Argentina: Isolation of an active principle from Lithrea molleoides

Screening of 91 native plants from central Argentina was carried out with the aim of finding new sources of anti-tyrosinase compounds. Extracts obtained from Achyrocline satureioides, Artemisia verlotiorum, Cotoneaster glaucophylla, Dalea elegans, Flourensia campestris, Jodina rhombifolia, Kageneckia lanceolata, Lepechinia floribunda, Lepechinia meyenii, Lithrea molleoides, Porlieria microphylla, Pterocaulon alopecuroides, Ruprechtia apetala, Senna aphylla, Sida rhombifolia, Solanum argentinum, Tagetes minuta and Thalictrum decipiens exhibited more than 90% inhibition of tyrosinase monophenolase activity at 1000 μg ml⁻¹. D. elegans,L. meyenii and L. molleoides were the most potent with IC₅₀ values of 0.48, 10.43 and 3.77 μg ml⁻¹, respectively. D. elegans, L. molleoides and T. decipiens also showed more than 90% inhibition of diphenolase activity at 1000 μg ml⁻¹, with the first of these being the most effective (IC₅₀ = 49.27 μg ml⁻¹). (Z,Z)-5-(trideca-4,7-dienyl)-resorcinol (1) was isolated from L. molleoides as an effective tyrosinase inhibitor with l-tyrosine or l-DOPA as substrates (IC₅₀ = 0.49 and 14.94 μg ml⁻¹, respectively). Compound 1 was 37 times more active in monophenolase inhibitory activity than kojic acid used as a reference. Effective extracts as well as (Z,Z)-5-(trideca-4,7-dienyl)-resorcinol could prove to be promising preservative agents for use in the food industry.     

Effects of phosphine and methyl bromide fumigation on the volatile flavor profile and sensory quality of dry cured ham

In separate experiments, randomized complete block designs with three replications were utilized to evaluate the effects of phosphine (PH₃) (0, 200 and 1000 ppm for 48 h) and methyl bromide (MB) (0, 4, 8, 16, and 32 mg/L for 48 h) fumigation concentration on the volatile flavor compound concentrations in dry cured ham. Minimal differences existed (P > 0.05) in the presence and concentration of aroma active compounds in both PH₃ and MB fumigated hams but sulfur and oxidation compounds were more prevalent (P < 0.05) in the fumigated treatments when compared to the control. As phosphine fumigation concentration increased, the residual concentration of phosphine also increased in the hams (P < 0.05), but all samples contained levels that are lower than the legal limit of phosphine allowed in stored food products (0.01 ppm) in the United States. A triangle test (n = 56) indicated that consumers could not discriminate (P > 0.75) between the control hams and those that were fumigated with PH₃. Minimal aroma/flavor differences existed among MB, PH3 and control hams, and dry cured ham that was fumigated with PH₃ was safe for consumption based on residual phosphine concentrations in the meat tissue.     

Effect of phosphorus on the fruit yield and food value of two landraces of Trichosanthes cucumerina L.- Cucurbitaceae

Studies were conducted in the early season of 2002 and 2003 at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria to evaluate the effect of phosphorus (P) on fruit yield and chemical composition of two landraces of Trichosanthes cucumerina L. For the purpose of the study, two landraces of T. cucumerina named Landrace I and Landrace II were used. The five levels of phosphorus evaluated were 0, 30, 60, 90 and 120 kg P₂O₅ ha⁻¹ using single super phosphate fertilizer (8% P). Statistical analysis showed that 90 kg P₂O₅ ha⁻¹ gave statistically significant higher fruit yield (16.4 tons ha⁻¹) compared to other P levels. The fruit yield of the two Landraces did not differ significantly. Except for crude protein content, the 90 kg P₂O₅ ha⁻¹ produced significantly higher ether extract (1.22 g 100 g⁻¹), crude fibre (1.93 g 100 g⁻¹), moisture content (90.5 g 100 g⁻¹), ash (0.90 g 100 g⁻¹), total sugars (0.81 g 100 g⁻¹) and ascorbic acid (28.7 mg 100 g⁻¹) than other P levels. The essential amino acids compositions were also significantly higher at 90 g 100 g⁻¹ compared to other lower P levels. Landrace I had significantly higher ether extract (0.90 g 100 g⁻¹) content than Landrace II (0.62 g 100 g⁻¹) while Landrace II in turn had significantly higher total sugar (0.76 g 100 g⁻¹) compared to Landrace I (0.61 g 100 g⁻¹). The essential amino acids composition is high and the oxalate composition is low. The high ascorbic acid and amino acid content together with a low oxalate composition suggested a strong basis for encouraging the cultivation of this indigenous fruit vegetable to augment nutrient requirement, improve diet and consequently alleviate poverty, preserve the biodiversity and increase the gene bank of neglected wild species of high quality nutrient sources.     

Composition of rosemary essential oil (Rosmarinus officinalis) as affected by drying method

The influence of the drying method on volatile compounds of Rosmarinus officinalis was evaluated. The drying methods tested were convective (CD) and vacuum-microwave (VMD), as well as a combination of convective pre-drying and VM finish-drying (CPD–VMFD). Rosemary drying kinetics was described by a simple exponential model for CD and VMD, while VMFD kinetics consisted of two periods: linear until a critical point and exponential beyond that point. Volatile compounds of rosemary samples were extracted by steam-hydrodistillation and analyzed by GC–MS. Thirty-four compounds were tentatively identified, with α-pinene, bornyl acetate, camphene and 1,8-cineole being the major components. The total volatiles concentration of fresh rosemary (135 g kg⁻¹) decreased considerably during both CD (87.2 g kg⁻¹) and VMD (61.9 g kg⁻¹). CPD–VMFD was the best option for drying rosemary because the time required was relatively short (30 min), and the aroma quality was good according to both instrumental (100 g kg⁻¹) and sensory analyses.     

Effects of skin and grilling method on formation of heterocyclic amines in chicken pectoralis superficialis muscle

Mutagenic heterocyclic amines (HAs) originate in processed proteinaceous foods. The effects of the presence of skin (with vs. without) and of grilling method (two plate vs. infrared) on the content of HAs in grilled chicken pectoralis superficialis muscle (temperature, 220 °C) were investigated. HA precursors (creatine, creatinine, free amino acids and carbohydrates) and HAs of these raw and grilled breast muscles were determined. The muscles originated from 24 birds of either sex (provenance Ross; aged 40-45 days). The HA content was determined in homogenates of the upper and lower surface slices of the grilled muscles (T_i = 82 °C). A higher content of total free amino acids was seen for the muscle (27.1 mmol kg⁻¹ raw meat) than for the skin (21.7 mmol kg⁻¹ raw meat). The creatine, creatinine and carbohydrate levels in the skin were below the limits of detection. The contents of creatine (31.8-38.7 mmol kg⁻¹) and creatinine (0.24-0.33 mmol kg⁻¹) in the breast muscle were determined. Relatively high levels were seen for glucose (23 mmol kg⁻¹ raw meat) and fructose (10 mmol kg⁻¹ raw meat) in the muscle, with other sugars present at low levels (<2 mmol kg⁻¹ raw meat). For the chicken muscle grilled on a two-plate grill, the contents of total HAs (PhIP, MeIQx, DiMeIQx, Harman and Norharman) were lower with the skin in place than in the muscle grilled without the skin (3.5 μg kg⁻¹vs. 4.8 μg kg⁻¹). Also, during infrared grilling with the skin, lower amounts of HAs were formed than with grilling on the two-plate grill (2.4 μg kg⁻¹vs. 3.5 μg kg⁻¹). On average, the infrared-grilled samples with skin contained 3-fold more total HAs than similar samples without the skin (2.4 μg kg⁻¹vs. 0.8 μg kg⁻¹), with the highest levels seen for PhIP and MeIQx.     

Effect of modifiers for As,Cu and Pb determinations in sugar-cane spirits by GF AAS

Palladium plus magnesium nitrates with and without Ir, Ru and W were evaluated for the simultaneous determination of As, Cu and Pb in cachaça by graphite furnace atomic absorption spectrometry. For 20 μL of sample, 5 μL Pd(NO₃)₂ and 3 μL Mg(NO₃)₂ dispensed together onto the Ir-coated platform of the THGA, analytical curves in the 0–30.0 μg L⁻¹ As, 0–1.50 mg L⁻¹ Cu and 0–60.0 μg L⁻¹ Pb were built up and typical linear correlation coefficients were always better than 0.999. The limit of detection was 1.30 μg L⁻¹ As, 140 μg L⁻¹ Cu and 0.90 μg L⁻¹ Pb. As, Cu and Pb contents in 10 cachaça samples agreed with those obtained by ICP-MS. Recoveries of spiked samples varied from 96% to 106% (As), 97% to 112% (Cu) and 92% to 108% (Pb). The relative standard deviation (n = 12) was typically 2.7%, 3.3% and 1.9%.     

Identification of antioxidants from rhizome of Davallia solida

Davallia solida rhizome has long been used as an herb tonic to treat osteoporosis, arthralgia, and arthritis. The aqueous extract of D. solida rhizome contains a high content of phenolic compounds [210.8 ± 4.6 mg catechin equivalents (CE)/g dry weight] and shows a strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (IC₅₀ = 15.93 ± 1.21 μg dry weight/ml). Further solvent partition of the aqueous extract yielded chloroform, n-butanol, and water layers. Among them, n-butanol layer has the highest phenol content (806.3 ± 12.3 mg CE/g dry weight) and DPPH scavenging potential (IC₅₀ = 3.93 ± 0.31 μg dry weight/ml). Isolation and purification from the n-butanol layer identified 12 compounds. They included four new compounds: 3′-O-p-hydroxybenzoylmangiferin (1), 4′-O-p-hydroxybenzoylmangiferin (2), 6′-O-p-hydroxybenzoylmangiferin (3), and 3-O-p-hydroxybenzoylmangiferin (4); as well as eight known compounds: mangiferin (5), 2-C-β-d-xylopyranosyl-1,3,6,7-tetrahydroxyxanthone (6), 4β-carboxymethyl-(−)-epicatechin (7), 4β-carboxymethyl-(−)-epicatechin methyl ester (8), eriodictyol (9), eriodictyol-8-C-β-d-glucopyranoside (10), icariside E₅ (11), and icariside E₃ (12). DPPH scavenging and Trolox equivalent antioxidant capacity (TEAC) analyses revealed that the most potent antioxidants are 1, 2, and 3, which exerted more than triple activity as compared with the positive controls, α-tocopherol and Trolox.     

Bovine neuronal vesicular glutamate transporter activity is inhibited by ergovaline and other ergopeptines

l-Glutamate (Glu) is a major excitatory neurotransmitter responsible for neurotransmission in the vertebrate central nervous system. Vesicular Glu transporters VGLUT1 and VGLUT2 concentrate (50 mM) Glu [Michaelis constant (measuring affinity), or K_m, = 1 to 4 mM] into synaptic vesicles (SV) for subsequent release into the synaptic cleft of glutamatergic neurons. Vesicular Glu transporter activity is dependent on vacuolar H⁺-ATPase function. Previous research has shown that ergopeptines contained in endophyte-infected tall fescue interact with dopaminergic and serotoninergic receptors, thereby affecting physiology regulated by these neuron types. To test the hypothesis that ergopeptine alkaloids inhibit VGLUT activity of bovine cerebral SV, SV were isolated from cerebral tissue of Angus-cross steers that were naive to ergot alkaloids. Immunoblot analysis validated the enrichment of VGLUT1, VGLUT2, synaptophysin 1, and vacuolar H⁺-ATPase in purified SV. Glutamate uptake assays demonstrated the dependence of SV VGLUT-like activity on the presence of ATP, H⁺-gradients, and H⁺-ATPase function. The effect of ergopeptines on VGLUT activity was evaluated by ANOVA. Inhibitory competition (IC₅₀) experiments revealed that VGLUT-mediated Glu uptake (n = 9) was inhibited by ergopeptine alkaloids: bromocriptine (2.83 ± 0.59 μM) < ergotamine (20.5 ± 2.77 μM) < ergocornine (114 ± 23.1 μM) < ergovaline (137 ± 6.55 μM). Subsequent ergovaline kinetic inhibition analysis (n = 9; Glu = 0.05, 0.10, 0.50, 1, 2, 4, 5 mM) demonstrated no change in apparent K_m. However, the maximum reaction rate (V_max) of Glu uptake was decreased when evaluated in the presence of 50, 100, and 200 μM ergovaline, suggesting that ergovaline inhibited SV VGLUT activity through a noncompetitive mechanism. The findings of this study suggest cattle with fescue toxicosis may have a decreased glutamatergic neurotransmission capacity due to consumption of ergopeptine alkaloids.     

Efficacy of sodium chlorite as an inhibitor of enzymatic browning in apple slices

Sodium chlorite (SC) is an effective sanitizer for inhibiting microbial growth. This investigation was conducted to determine the efficacy of SC as a browning control agent for use on fresh-cut apple slices, applied alone, or in conjunction with organic acids. Additionally, the authors compared the efficacy of SC to that of acidified sodium chlorite (ASC) and to several other salts and examined the effect of pH and several different organic acids on efficacy of SC. The fresh-cut apple slices were dipped in treatment solutions for 1 min, then drained and placed in plastic containers at 20 °C for 24 h, and finally stored in polyethylene bags at 5 °C for 2 weeks. Color was measured periodically during storage. Lightness (L) values for all treated and control samples measured at 4 h, 24 h, and 2 weeks of storage were compared to L value for untreated samples measured immediately after cutting. Percent decrease in L-values was calculated for each sample at each time interval. Apple slices treated in ASC or SC solution had a significantly smaller decrease in L value indicating less browning than those treated in citric acid or water control at 4 h (P < 0.01), and with the exception of 1 g L⁻¹ ASC and 0.1 g L⁻¹ SC, all other ASC and SC treated slices still had significantly less browning than those for the water control (P < 0.01) at 24 h. After 2 weeks of storage, only SC (0.5–1.0 g L⁻¹), sodium bisulfite (0.5 g L⁻¹) and calcium l-ascorbate (10 g L⁻¹) continued to inhibit browning. Treatment with 0.5 g L⁻¹ SC and pH adjusted in the range from 3.9 to 6.2 using citric acid (CA) reduced browning more effectively than 0.5 g L⁻¹ SC without pH adjustment. Two organic acids, salicylic acid and cinnamic acid, when added to SC solution, were found to achieve even better inhibition of browning than CA at the same pH value.     

Sterol and vitamin D2 concentrations in cultivated and wild grown mushrooms: Effects of UV irradiation

Raw and processed mushroom samples including wild grown (chanterelles and king bolete) and cultivated samples (white and brown button, portabella, shiitake, oyster) were bought from the food market and analysed for sterols and vitamin D₂ contents. The different commercial mushrooms selected are abundant in almost every Swedish and European supermarket or outdoor market. Ergosterol was the most abundant sterol found in mushrooms present in somewhat higher concentrations in cultivated mushrooms (4.0-5.0 mg/g dry matter (d.m.)) than those found in wild mushrooms (1.7-3.5 mg/g d.m.). In addition, three closely related minor sterols, including ergosta-7,22-dienol, ergosta-5,7-dienol, and ergosta-7-enol were identified. Chanterelles and king bolete were found to be good sources of vitamin D₂ (0.7-2.2 μg/g d.m.) compared with cultivated mushrooms that had a low content (< 0.1 μg/g d.m.). Canned samples of Agaricus bisporus/white were slightly lower in ergosterol and vitamin D₂ compared to fresh samples. Irradiation with UV light in the A region (366 nm) only slightly affected ergosterol and vitamin D₂ content. In contrast, irradiation with UV light conducted in the C region (254 nm, 0-2 h, 20 cm distance) for fresh white button mushrooms and freeze-dried chanterelles resulted in nonsignificant decrease in ergosterol content, whereas vitamin D₂ increased up to 9-fold (Cantharellus tubaeformis) and 14-fold (A. bisporus/white), respectively.     

Crystallization kinetics of palm oil in blends with palm-based diacylglycerol

Crystallization kinetics of palm oil (PO) in the presence of different concentrations (2, 5, 10, 30 and, 50% w/w) of palm-based diacylglycerol (PB-DAG) were investigated over different ranges of crystallization temperatures. Addition of 30 and 50% (w/w) of PB-DAG (high concentrations) increased significantly (P < 0.05) the melting point and crystallization onset while addition of 2 and 5% PB-DAG did not have significant (P > 0.05) effect. PO and PO blends with 2 and 5% of PB-DAG showed crystal transformation at crystallization temperatures (T_Cr) of 26, 26, 26.5 °C, respectively as reflected in corresponding changes of the Avrami parameters at below and above these T_Cr. This was especially evident for the blends containing 2 and 5% of PB-DAG. Individual comparison of induction time (T_i), Avrami exponent (n), Avrami constant (k) and half-time of crystallization (t_1/2) of blends classified under various supercooling ranges based on the supercooling closeness (± 0.1 °C), showed that addition of 5% of PB-DAG in most of the supercooling ranges significantly (P < 0.05) reduced nucleation rate as well as crystal growth velocity of PO. This was reflected in the significantly (P < 0.05) higher T_i and t_1/2 and lower k. Although the presence of 2% of PB-DAG was found to have inhibitory effect on PO crystallization, this effect was not significant (P > 0.05). Mode of crystal growth attributed to n was changed significantly only in presence of 5% of PB-DAG. Furthermore, presence of 10% PB-DAG showed ??'-stabilizing effect on PO. On the other hand, high concentrations of PB-DAG were found to significantly (P < 0.05) reduce T_i as well as t_1/2 and also increase k suggesting their promoting effects on nucleation and crystallization rate of PO even with the close supercoolings. In addition, they changed crystal growth mode of PO. Amongst the different concentrations of PB-DAG investigated, blend containing 50% of PB-DAG as compared to PO, not only, have healthier benefits but also, may have greater potential applications in plastic fat products due to its unique physical properties.     

The physicochemical characteristics and hydrophobicity of high amylose starch–glycerol films in the presence of three natural waxes

The film forming behaviour and hydrophobicity of high amylose (HA) starch in the presence of three different natural waxes (beeswax, candelilla wax and carnauba wax) were studied in the presence and absence of Tween-80. The HA starch:glycerol (G) ratio was maintained at 80:20 (on dry solid basis) and the concentration of wax was varied from 5% and 10% (w/w). The melted wax samples were homogenized with HAG dispersion with or without Tween-80 and the films were prepared by solution casting. The hydrophobicity and water-barrier properties in these films were determined by using contact angle (CA), water vapour permeability (K_w) tests, and water sorption isotherm at 0.529 RH and 20 °C. The K_w values of the HAG films decreased significantly (p < 0.05) with the addition of 5% concentration of these waxes. Then the addition of Tween-80 to the HAG + wax films increased the K_w values significantly (p < 0.05). The presence of these waxes in the presence and absence of Tween-80 resulted into different sorption isotherms and the water adsorptivity and moisture diffusion coefficient values were also affected. The presence of Tween-80 increased the CA in HAG + carnauba wax films while the CA was found to decrease in the case of other two waxes. The highest hydrophobicity was observed in HAG + carnauba wax + Tween-80 films in which the CA was >80.0° both at 5% and 10% (w/w) wax concentration. These higher CA values in HAG + carnauba wax + Tween-80 films were found to be related to the higher surface roughness in these films.