Changes in Tocochromanol Content in Seeds of <Emphasis Type="Italic">Brassica napus</Emphasis> L. During Adverse Conditions of Storage

Tocopherols and plastochromanol-8 were evaluated in seeds of Brassica napus L. during adverse conditions of storage at different temperatures (25 and 30 °C) and moisture levels (10, 12.5 and 15.5%). Both temperature and moisture content of seeds had a significant effect on the hydrolysis of triacylglycerols in rapeseed oil and on the contents of tocopherols and PC-8. The biggest losses of tocopherols (a drop by 14.4% after 18 days) were recorded for seeds with a moisture content of 15.5% and stored at a temperature of 30 °C. Losses of the α-T homologue were bigger than those of γ-T. The loss of PC-8 ranged from 4 to 24% depending on storage conditions and it was almost two times bigger than the loss of tocopherols.     

Degradation of Phytosterols During Near-Ambient Drying of Rapeseeds in a Thick Immobile Layer

The effect of the drying method applied and subsequent rapeseed storage on changes in phytosterols was determined. After harvest, rapeseeds were dried by the near-ambient method in a thick immobile layer of 2 m and using air heated to a temperature of 60, 80 and 100 °C. Analyses of phytosterol contents were performed immediately after drying and after 6 and 12 months of storage at a temperature of 10 ± 2 °C. Results showed a significant effect of drying conditions, cultivar-specific differences and storage time on the contents of phytosterols. Near-ambient drying of seeds resulted in a reduction in total sterol contents by 6–20 %, while for drying with hot air it was by 14–40 %. The level of sterols decreased by 13–18 % after a 1 year storage of seeds dried by the near-ambient methods. A reduction in 12–22 % in sterols for seeds dried by high temperature occurred after 1 year of storage.     

Corn,Rice, and Wheat Seed Drying by Two-Stage Concept

Corn, rice, and wheat seeds with an initial moisture content (IMC) of 20–25% wb were dried to moisture content below 18% wb at 40–80°C in a fluidized bed dryer (FBD) and spouted bed dryer (SBD) and the seeds with IMC 18% wb were dried to below 14% wb at air temperatures 18–30°C and relative humidity 60–70% by an in-store dryer (ISD). As a result, it appears that a two-stage drying concept is feasible in drying high-moisture-content seeds due to the high germination rate of dried seeds. Nonetheless, the drying temperature must be carefully selected. A drying temperature of 40°C was clearly safe for all samples, whereas more than 90% of wheat seeds still germinated after drying at 60°C in FBD. Furthermore, drying seeds with IMC 18% wb by ISD was safe under specified drying conditions.     

Effects of Time and Temperature on the Viscoelastic Properties of Chinese Fir Wood

The effects of time and temperature on dynamic viscoelastic properties of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook) were investigated using dynamic mechanical analysis in this study. The isothermal tests were applied to the small clear specimens with a moisture content of about 0.6% at constant temperatures ranging from 25 to 200°C for 550 min at atmospheric pressure. Changes in storage modulus and loss tangent with heating time were examined. The results indicated that heating time mainly resulted in thermal softening, thermal degradation of wood, and the reduction of wood stiffness. At more than 60°C, the reduction in storage modulus was accelerated generally as the wood was subjected to a higher temperature or longer heating time. At constant temperatures of 140 and 160°C, a relaxation phenomenon was observed with a slight change in weight, which could be attributed to the relocation of lignin molecules. At the temperature range of 140 to 180°C, the higher the heating temperatures, the earlier the tanδ peak appeared. It is suggested that the wood thermal softening occurs at higher temperatures with shorter heating times or at lower temperatures with longer heating times. At temperatures of 180 and 200°C, the loss of amorphous polysaccharides due to thermal degradation is considered to be the main factor affecting wood viscoelasticity.     

Influence of Processing Conditions on the Physicochemical Properties and Shelf-Life of Spray-Dried Palm Sugar (Arenga pinnata) Powder

The influence of spray-drying conditions on some physicochemical properties of palm-sugar powder ( Arenga pinnata ) was studied. Twenty tests were carried out according to a central composite design. Independent variables were: inlet temperature (150–190°C), feed flow rate (9–21 g/min), and maltodextrin concentration (14–25%). Process yield, hygroscopicity, and outlet temperature were analyzed as responses. Results revealed that increasing inlet temperature resulted in higher process yield and outlet temperature and a lower hygroscopicity. Similarly, higher inlet temperature led to lower moisture content, dissolution rate, and total phenolic content of the powder. Conversely, the feed flow rate negatively influenced process yield and hygroscopicity, and positively influenced moisture content. Moreover, maltodextrin exhibited negative influence on process yield and hygroscopicity, respectively. Moreover, storage (30°C, six months) led to noticeable losses in flowability and wettability. Powder morphology was also influenced by the inlet temperature. Lower inlet temperature resulted in particles with shrivelled surfaces while higher temperature produced a greater number of larger particles with smooth surfaces.     

Effect of Roasting on Flaxseed Oil Quality and Stability

The food industry is interested in the application of roasted flaxseeds because the treatment improves their sensory acceptability. However, it also influences flaxseed oil nutritional quality and stability. The aim of the study was to analyze oxidation changes in situ and in flaxseed oil compounds (fatty acids, phytosterols, tocochromanols) and Maillard reaction products (MRP) after roasting. The effect of the roasting temperature (160–220 °C) and flaxseed cultivars (golden- and brown-seed) was taken into consideration. The results showed that the selection of roasting temperature (<200 °C vs. ≥200 °C) and flaxseed cultivar significantly influenced the nutritional quality and oxidative stability of roasted flaxseed oils. The roasting of flaxseeds did not significantly affect the fatty acid profiles of oil but it influenced the content of the other bioactive compounds. As the roasting temperature increased (≥200 °C), the γ-tocopherol degradation decreased, whereas the content of plastochromanol-8 increased. The total content of phytosterols in the roasted seed samples was higher than in the raw seeds but there was no correlation between the phytosterol content and roasting temperature. The temperature ≥200 °C significantly accelerated in situ oil oxidation during roasting. On the other hand, these conditions favored the MRP formation, which may have slowed down the dynamics of oil oxidation during storage. There was lower oil oxidation in the brown-seed cultivar; in consequence, the tocopherol retention was higher than in the golden-seed cultivars. The results could be useful for the selection of the best cultivars and treatment conditions to decrease unfavorable changes in flaxseed oil nutritional quality and stability.     

Effect of Fatty Acid Unsaturation on Phytosteryl Ester Degradation

This study examined the thermo-oxidative degradation of stigmasterol fatty acids esters. Stigmasterol stearate, oleate, linoleate and linolenate were synthesized by chemical esterification and their purity evaluated by ¹H-NMR and GC–MS. The degradation of stigmasterol esters was examined after heating them at 60 and 180 °C for 1, 2, 4, 8 and 12 h. It was established that stigmasterol esters were prone to thermo-oxidative degradation, with time and temperature affecting the degree of degradation. The unsaturation of fatty acids affected the rate of stigmasteryl ester degradation. The kinetics of StS and StO degradation were similar and the additional double bonds in StL and StLn resulted in their faster decomposition. The esters degraded faster at 180 than at 60 °C. The sterol and fatty acid molecules degraded at different rates, such that the fatty acid moiety deteriorated faster than the sterol at both temperatures, independent of the time of heating and the level of unsaturation.     

Variability of Phytosterols in Jatropha curcas Germplasm

Jatropha curcas L. has great potential for biofuel and phytosterol production. The objective of this research was to evaluate G × E variability for kernel phytosterol content and composition in Jatropha germplasm. Freshly matured seeds from 21 accessions grown in Málaga, Spain were collected at two stages of development. Significant genetic variation was detected for total kernel phytosterol content, which ranged from 2,246 to 2,883 mg kg^?1; and stigmasterol concentration, which ranged from 7.6 to 11.5 % of the total phytosterols. An accession with 9.2 % Δ⁵‐avenasterol was also identified. The coefficient of variation for kernel phytosterol content and stigmasterol concentration was 6.2 and 14.0 % respectively between accessions and 7.2 and 10.2 % respectively within accessions. Accordingly, evaluation of plant to plant variation is advisable. The existence of variability for kernel phytosterol content and composition in Jatropha will enable breeding for enhanced levels of these compounds.     

Effects of Storage Temperature and Water Activity on the Degradation of Carotenoids Contained in Microencapsulated Chili Extract

The aim of this work was to evaluate the effects of storage temperature and water activity on degradation of carotenoids contained in microencapsulates of non-aqueous extracts from chili (NAEC). Total carotenoids content and adsorption isotherms of microencapsulated NAEC in a 1:1 weight ratio with gum Arabic-maltodextrin DE 20 (GA 50%–MD50%) were determined at 25, 35, and 40°C. The isotherms were fitted using the Guggenheim-Anderson-de-Boer model and their enthalpies and entropies, both differential and integral, were estimated by the Clausius-Clapeyron method. The minimum integral entropy was considered as the point of maximum stability at which water less readily participates in degradation reactions. Zones of minimum integral entropy were found between 7.56–8.30, 6.10–6.95, and 5.15–6.04 kg H₂O/100 kg dried solids, corresponding to water activity (a_w) of 0.210–0.239, 0.238–0.277, and 0.262–0.313 at 25, 35, and 40°C, respectively. Total carotenoids content (CT) degraded over time, but degradation of carotenoids was lower in microcapsules stored at 25°C than those stored at 35 or 40°C. The morphology of microcapsules was altered at a_w > 0.6, including swelling of the polysaccharide matrix was presented, and possible subsequent dissolution of the wall material, which indicates a high rate of carotenoid degradation. When microencapsulated NAEC were storage between 0.2–0.6 of water activity, the highest glass transition temperatures were achieved. In this range, the wall materials of the microcapsules suffer less microstructural modifications, associated with the minimum level of degradation of carotenoids. Sometimes, in this water activity range, the zones of minimal entropy were observed.     

Effect of drying and storing tung seeds on quality of the oil and milling characteristics of the seeds

1. Tung seeds, hulled but with most of the shells intact, were artificially dried at two temperatures in December and January and put in storage in bags in a well ventilated shed, along with similar seeds which had not been artificially dried. At bimonthly intervals tests on stored seeds were made on a commercial serew press.
2. The acid value of oil in the intact seeds put in storage at 10% moisture content early in December and late in January had risen only slightly, from 5 to 0.8–1.5, by the following April.
3. Intact seeds dried to about 10% moisture at temperatures of 158° F. and about 172° F. (155–190° F.) processed in the screw press as well the following April as they did when put in storage in early December, and there was no deterioration in the quality of the oil.
4. Intact seeds which were dried from 26% moisture to about 10% moisture in late January at 155–212° F. (the temperature remained at 212° F. for at least an hour) did not process efficiently after two months' storage, nor did the material stored at the same time without artificial drying.
5. Caution should be used in storing seeds for long periods after drying at temperatures approaching 212° F. or with high moisture contents (20% or above) until more experience is available.

     

Moisture Adsorption Isotherms of Watermelon Seed and Kernels

The moisture adsorption isotherms of watermelon seeds and kernels from Citrullus lanatus Cv Mateera and Citrullus vulgaris Cv Sugar baby were obtained using standard static method with saturated salt solutions over a range of water activities from 0.113 to 0.92 at 20–60°C. The adsorption capacity of seeds decreased with the increase in temperature at constant water activity. Sorption models were used to explain the adsorption behavior involving water activity and moisture content (Type I) and also temperature (Type II). Oswin's models gave best fit among Type I with coefficient of determination of 0.953–0.995, standard error of 0.031–0.0571, mean relative error of 0.071–0.152, and scattered residual plots. Modified Oswin was the best fit model among Type II for the seeds and kernels of both the cultivars with coefficient of determination of 0.997–0.999, standard error of 0.151–0.255, mean relative error of 0.018–0.244, and scattered residual plots. The net isoelectric heat of adsorption, estimated from Clausius-Clapeyron decreased from about 27.0 to 0.5 kJ/mol in kernels and 18.0 to 0.5 kJ/mol in seeds of both the cultivars as the moisture content increased from 5 to 25% (dry basis).     

Phytosterol accumulation in canola, sunflower, and soybean oils: Effects of genetics, planting location, and temperature

To assess the potential of traditional selection breeding to develop varieties with increased phytosterol content, we determined concentrations of those sterols in canola, sunflower, and soybean seed oils produced from breeding lines of diverse genetic backgrounds. Seed oils were extracted and saponified, and the nonsaponifiable fractions were subjected to silylation. The major phytosterols brassicasterol, campesterol, stigmasterol and β-sitosterol, were quantified by capillary gas chromatography with flame-ionization detection. Canola contained approximately twice the amount of total phytosterols (4590–8070 μg g⁻¹) as sunflower (2100–4540 μg g⁻¹) or soybean (2340–4660 μg g⁻¹) oils. Phytosterol composition varied among crops as expected, as well as within a crop. Both genetic background and planting location significantly affected total phytosterol concentrations. Soybean plants were maintained from flower initiation to seed maturity under three temperature regimes in growth chambers to determine the effect of temperature during this period on seed oil phytosterol levels. A 2.5-fold variability in total phytosterol content was measured in these oils (3210–7920 μg g⁻¹). Total phytosterol levels increased with higher temperatures. Composition also changed, with greater percent campesterol and lower percent stigmasterol and β-sitosterol at higher temperatures. In these soybean oils, total phytosterol accumulation was correlated inversely with total tocopherol levels. Owing to the relatively limited variability in phytosterol levels in seed oils produced under field conditions, it is unlikely that a traditional breeding approach would lead to a dramatic increase in phytosterol content or modified phytosterol composition.     

Methanol-Water Extraction of Saponins From Seeds of Saponaria Vaccaria L. — Calibration Equation,Extraction Condition Analysis,and Modeling

Bisdesmosides, monodesmosides, and other bisdesmosidic saponins were observed in the particles of Saponaria vaccaria L seeds (15.35% dry basis) with diameter of 0.044 to 1.19 mm and an average thickness of 124 µm as investigated with liquid chromatography-mass spectroscopy at methanol concentration of 30%, 50%, 70%, and 90% (vol., aq.), temperature of 30°C, 45°C, and 60°C, and eight extraction time intervals between 1 and 180 min. The saponins yield increased significantly with temperature (45°C to 60°C) and methanol concentration (50% to 70%) with negligible effect of moisture content. The maximum yield was obtained at 60°C for 70% methanol concentration and 30 min of extraction time. The mass transfer properties of the test material may have potentials for modeling, simulation and optimization of similar products and processes. A diffusional mathematical model simulated extraction kinetics, and estimated partition coefficient, and effective diffusivity of saponins very well.     

Evaluating a Solar Dryer for In-Shell Drying of Split Pistachio Nuts

Abstract

A thin-layer forced air solar dryer was designed to study the feasibility of drying pistachio nuts. The dryer was tested during the 2001 and 2002 drying seasons. The maximum temperature in the solar collector reached 56°C, which was 20°C above the ambient temperature. The required drying time was 36 h. During the first day of drying (0800 to 1700 h) the moisture content dropped to about 21% (wb). The final moisture content of the dried nuts was 6% wb, which was 1% below the recommended storage moisture. The drying constant of the pistachio nuts during solar drying was determined using two mathematical models, a one-term series solution of Fick's diffusion equation and an exponential decaying model. There was no significant difference between the two models (α = 0.05). In general, the quality of solar dried nuts was better than the conventional heated air due to slower drying rates.     

Effect of heat treatment and pH on the thermal,surface, and rheological properties of <Emphasis Type="Italic">Lupinus albus</Emphasis> protein

Endosperm from hand-dissected and- dehulled Lupinus albus seeds was milled into meal, sieved through a 40-mesh screen, and suspended in phosphate buffers (pH 4, 6.8, and 8) at 20% (wt/vol). The suspensions were treated at 75, 90, or 100°C for 1 h. The heat-treated protein was characterized by SDS-PAGE, free zone capillary electrophoresis (FZCE), and DSC; and its surface hydrophobicity, surface tension, and rheological properties were examined. The presence of high M.W. aggregates was apparent from SDS-PAGE and FZCE results. Solubility was lowest at pH 4 and 100°C. DSC analysis was performed on low moisture content samples (3.1%) and 20% (wt/vol) suspensions. DSC analysis at 3.1% moisture content showed a glass transition around 85°C and an exothermic transition at 160°C, whereas the protein suspension showed a more thermally stable protein as indicated by the higher ΔH values. Lupin protein was surface active as demonstrated by its effectiveness in reducing the surface tension of the aqueous phosphate buffer. Surface hydrophobicity of the heat-treated protein decreased as the treatment temperature increased, which supports the SDS-PAGE results. The highest level of aggregation was noted at 90°C and pH 6.8 as indicated by low surface hydrophobicity values. Rheological studies showed direct relationships between the shear storage modulus (G′) of the lupin meal suspension and both pH and temperature treatment, although this effect is minimal at the highest temperature (100°C) and pH 6.8.     

A Small-Scale Pneumatic Conveying Dryer of Rough Rice

This article studies the possibility of reducing the high initial moisture content of wet rough rice using a small-scale low-cost pneumatic conveying dryer as a first stage dryer. The parameters investigated are final moisture content, surface temperature of rough rice, head rice yield, drying rate, power consumption per unit mass of evaporated water, and physical characteristics of rice. Parametric effects of the following variables are examined: velocity of drying air from 20 to 30 m/s, feed rate of rough rice from 150 to 350 kg/h, initial moisture content from 22 to 26% (wet basis), and drying air temperature from 35 to 70°C. From the experimental results, it is found that this drying method can be used for fresh rough rice with an initial moisture content of over 24% (wet basis). The drying process is able to lead to very rapid drying without any grain quality problems such as cracks in the rice kernel. The moisture content can be reduced to approximately 18% (wet basis) or about 5–6% of the initial moisture content within 3–4 s. The optimal drying air temperature is in the range of 50 to 60°C. A comparison of pneumatic conveying drying data obtained from the present study with fluidized bed drying data reported in the open literature is also discussed.     

Fatty Acid Profile and Bioactive Compound Extraction in Purple Viper's Bugloss Seed Oil Extracted with Green Solvents

Oil extraction from seeds of purple viper's bugloss (Echium plantagineum) was carried out using different solvents (chloroform:methanol, n-hexane, ethanol, 2-propanol and ethyl acetate) at room temperature and also using Randall extraction. Extraction yields were calculated and oils were analyzed in terms of fatty acid profiles and distribution among lipid classes, total polyphenol content, oxygen radical absorbance capacity (ORAC) and phytosterol content. No considerable differences were found on fatty acid profiles and distribution in oils regardless of the solvent and temperature used for the extraction. However, ethanol combined with Randall extraction (85 °C for 1 hour) offered the best results in terms of total polyphenol content (20.9 mg GAE/100 g oil), ORAC (468.0 μmol TE/100 g oil), and phytosterol amount (437.2 mg identified phytosterols/100 g oil) among all assayed extraction methods. A higher extraction temperature led to significantly higher concentrations of bioactive compounds and ORAC values in the oil when ethanol or 2-propanol were used as extracting solvent, but that was not the case using n-hexane except for the concentrations of β-sitosterol and stigmasterol, which were significantly higher using Randall extraction than room temperature extraction with n-hexane. Ethanol is classified as a “green solvent,” and it could be considered a suitable option to produce oil from E. plantagineum seeds with a higher antioxidant capacity and bioactive compound concentration than the current commercial oil, which is usually extracted with n-hexane.     

The rate of development of acidity in stored tung seeds and kernels

Summary Whole tung seeds, whole kernels, and chopped kernels of high, medium, and low moisture contents were sealed in tin cans and stored in incubators maintained at 25°, 31°, and 38°C. At intervals samples were removed and the acid value of the oil determined. The different temperatures used had slight effect on the rate of development of free fatty acids in the oil of the whole seeds and kernels, but the higher temperatures greatly increased the rate of development of free acid in the chopped kernels. Whole seeds containing 7% and 12% moisture were stored for 4 weeks and seeds containing 17% moisture were stored for 2 weeks, during which periods the oils developed free fatty acids equivalent to acid values of 2.0 or less. Under none of the conditions used did the acid values of the oils exceed 8.0 after storage for 13 weeks. Whole kernels developed even less free fatty acids than seeds stored under similar conditions. Kernels containing 4% and 6% moisture were stored for 12 weeks during which period the acid value of the oil never exceeded 1.5. Even in kernels containing 12% moisture the acid value of the oil did not exceed 6.0 at the end of 12 weeks. Chopped kernels with moisture contents of 5% and 7% could be stored for 12 days without developing an acid value in the oil of more than 8.0. However chopped-kernels with a moisture content of 12% developed an acid value in the oil in excess of 8.0 in less than a week. Whole seeds with as much as 15% moisture could probably be stored for several weeks without developing an objectionable amount of free fatty acids. Since commercial hulled “nuts” practically always contain some broken kernels, to avoid development of free fatty acids in storage they should be dried to 10% or less moisture before storage. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Effect of Relative Humidity on the Antioxidant Activity of Spray-Dried Banana Passion Fruit (Passiflora Mollisima Baley)-Coated Pulp: Measurement of the Thermodynamic Properties of Sorption

The antioxidant activity of the spray-dried banana passion fruit-coated pulp with maltodextrin10 DE was evaluated throughout 30 days of storage at a temperature of 25°C for different relative humidity values It was influenced by the relative humidity throughout the 30 days of storage. In addition, the sorption equilibria of water for spray-dried banana passion fruit-coated pulp with maltodextrin 10 DE at 25, 35, 45, and 55°C, over a range of relative humidity levels from 0.113 to 0.843, was determined using a gravimetric static method. The isosteric heat and Gibbs free energy were calculated from the sorption equilibrium. The Guggenheim-Anderson-Boer (GAB) and Brunauer-Emmett-Teller (BET) models were tested to fit the experimental data. The GAB model was found to be the most suitable for describing the sorption curves, exhibiting an error smaller than 10% and an r greater than 0.99. The monolayer moisture content values for the sorption at different temperatures that were calculated using the GAB model ranged between 0.05315 to 0.05716 g water/g dry matter. The sorption curves exhibited a Type III behavior. The isosteric heat decreased with increasing moisture content while the Gibbs free energy increased.     

Storage Stability of Carrot Chips

Water activity combined with the glass transition temperature can be used to predict the shelf life of foods. Water sorption isotherms and glass transition as a function of moisture content were determined for carrot chips after vacuum frying. The GAB model was fitted to the measured sorption data while the Gordon Taylor equation was used to model the water plasticization effect. The critical moisture content and the critical water activity at which the glass transition occurs were obtained at selected storage temperatures. The changes in moisture content, fat content, water activity, breaking force, β-carotene content, ascorbic acid, and acid value of vacuum-fried carrot chip at selected storage temperatures (0, 10, 25°C) during a 6-month storage period were investigated. The estimated shelf life of carrot chip, defined by the degradation time of the acid value at different storage conditions, was determined.