Elnaz Ghaem far; Seyed Mahmoud Reza Hojjati
Abstract
Introduction: Adding color to Foods can make them more appealing to consumers, to allow consumers to identify what taste to expect from a product, and to protect sensitive flavors from light. Color has always played a vital role in food selection and acceptance, and colorants are added to foods to alleviate ...
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Introduction: Adding color to Foods can make them more appealing to consumers, to allow consumers to identify what taste to expect from a product, and to protect sensitive flavors from light. Color has always played a vital role in food selection and acceptance, and colorants are added to foods to alleviate color lost during processing. Caramel color, from the palest yellow to the deepest brown, accounts for more than 80% (by weight) of all colorants added to the foods we eat and drink (Sengar, et al., 2014).Because of sensitivity of liquid colors to oxidation, light and heat and difficulties in their handling and incorporating, dried pigments have been developed. Microencapsulation is a technique to package materials in the form of micro- and nano-particles. There are different methods for encapsulation in the food industry. Freeze drying which has a long dehydration period, has been used as a simple technique in encapsulating water-soluble essential oils and natural aromas or drugs (Khazaei, et al., 2014). In this work, in addition to liquid caramel color production, encapsulation of liquid color with freeze drying technique through wall materials of maltodextrin and Arabic gum were carried out. The stability of microencapsulated color was then evaluated.
Materials and Methods: Rish baba grape and Kabkab date syrup were obtained from local market. Ammonium chloride, citric acid, sodium hydroxide, tween 80, Arabic gum were purchased from Merck (Germany). Glycine and maltodextrin were obtained from Sigma-Aldrich (USA) and Dextrose Company (Iran), respectively. In this study, the effect of factors such as type of catalyst (ammonium chloride-glycine), concentration of catalyst (0.5-2 molar), the pH of reaction (4-5), reaction time (60-120 minutes) on liquid color intensity of caramel produced from two natural sources of date and grape were investigated based on fractional factorial experimental design. For production of liquid caramel color, grape/date syrup was heated while being stirred to 65ᵒ C. Catalysts were then added to syrup and heated to 110ᵒC. water was added to reaction product and centrifuged. The solvent was removed by rotary evaporator (IKA HB 10, Germany).The resulting caramel color was stored under refrigeration at 4ᵒ C. In order to produce powder of caramel color, wall materials including Arabic gum and maltodextrin were dissolved in distilled water at ambient temperature to obtain 20% total solids concentration and stirred for 30 minutes at 60ᵒC. The mixture of liquid caramel color, tween80, and wall material solution was mixed in a ratio (w/w) of 1:4 (liquid caramel color: wall material) and stirred for 15 minutes. The mixture was then dried in a freeze dryer (ALPHA 1-2 LD PLUS, Germany) for 24 hours. The blank sample was prepared without wall materials and freeze-dried in similar conditions with other samples in 24 hours. Dried materials were collected and stored in brown glass bottles with screwed caps at 4⁰C until analysis. The powders were characterized using TGA/DSC thermogravimetric analysis (METTLER TOLEDO, USA), scanning electron microscopy (SEM) (TESCAN vegar, Czech Republic) and X-ray diffraction (XRD) (Billerica, MA, USA) to confirm the structural and morphological aspects of powders.
Results & Discussion: The results showed that the type of catalyst had no effect on the intensity of the colors and maximum color intensity (0.174 for color produced from grape and 0.15 for color produced from date) was obtained under these conditions: 120 minutes for reaction time, pH value = 4 and catalyst concentration of 2 molar. Results of thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) indicated the increase of thermal resistance by microencapsulation process so that initial decomposition temperature for liquid form, without wall material, with Arabic gum and with maltodextrin for grape source were 114,138,162,185°C respectively and for date source were 113,131, 143, 180°C respectively. Results of Scanning electron microscope demonstrated that size of the powders were 11-55 μm. In conclusion, microencapsulation by freeze drying could be recommended as a suitable method for stabilizing caramel color.
Saeedeh Zarbakhsh; Somayeh Rastegar
Abstract
Introduction: The date palm (Phoenix dactylifera L.) plays an important social, environmental, and economic role for many people living in arid and semiarid regions of the world. Fruits of the date palm are very commonly consumed in many parts of the world and considered as a vital component of the diet ...
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Introduction: The date palm (Phoenix dactylifera L.) plays an important social, environmental, and economic role for many people living in arid and semiarid regions of the world. Fruits of the date palm are very commonly consumed in many parts of the world and considered as a vital component of the diet and a staple food in most Arab countries. Nearly 2000 cultivars of date palm are known in the world, but only some have been evaluated for their performance and fruit quality. Dates are rich in certain nutrients and provide a good source of rapid energy, due to their high carbohydrate content (70–80%). Moreover, date fruits contain fat (0.20–0.50%), protein (2.30–5.60%), dietary fiber (6.40–11.50%), minerals (0.10–916 mg/100 g dry weight), and vitamins (C, B1, B2, B3, and A) with very little or no starch. The aim of the present work was to investigate the chemical composition, carbohydrate, and antioxidant capacity of two date palm varieties grown in Hormozgan and Farce province.
Materials and methods: After collection, all date samples were washed with tap water, and the seeds were removed, dried at room temperature under shadow. Moisture content was determined by drying samples in oven at 60 °C until constant weight was attained. The determination of proteins was done by Bradford method. Color measurement of fruit made using a portable CR-400 colorimeter (Minolta Chroma Meter CR-400 Osaka japan).Total polyphenols were determined as described by Waterhouse, 2002.The results were expressed as milligram gallic acid equivalents per 100 g of dry weight (mg GAE/100 g DW). Total flavonoids content (TFC) of the date extracts were measured according to the colorimetric assay of Chang et al., 2002. The hydrogen peroxide (H2O2) scavenging ability of palm dates was carried out using 2, 2-diphenyl- 1-picryl hydrazyl (DPPH) spectrophotometric method described by Choi with some modification.
Results and Discussion: Based on the results, The highest fruit length (43.6 mm), weight of pulp (9.3 g) and antioxidant activity (57 mgFW) were found in Piarom date of Hajiabad and the highest phenol (20.7 mg/gFW), TSS (77.3%) and titratable acid (0.023%) were recognized in Zahedi date of Hajiabad. Although date varieties from Jahrom showed better color index and tannin content than Hajiabad date. In comparison between two varieties, Piarom date was better in fruit weight (28.3 g), moisture content and protein content (7%) and flavonoids (22.2 mg CEQ/gFW) than the Zahedi date. However, the carbohydrate of Zahedi date (85%) was higher than the Piarom date. Therefore, in addition to the variety, location and climate condition also have the important role in determining the nutritional value of date palm fruit.
Parnian Pezeshki; Abdolmajid Maskooki; Mohammad Elahi; Seyed Ali Mortazavi
Abstract
Baker's yeast is one of the most important additives for improving the bread quality and molasses is a commonly used source of sugars for producing baker's yeast. Nowadays, due to increasing the fermentation industries and limitation in suitable sources of sugars, the use of other carbohydrate sources ...
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Baker's yeast is one of the most important additives for improving the bread quality and molasses is a commonly used source of sugars for producing baker's yeast. Nowadays, due to increasing the fermentation industries and limitation in suitable sources of sugars, the use of other carbohydrate sources may be considered.In this study, the possibility of baker's yeast production in three cultures of date , raisin , enzymatic hydrolyzed whey and molasses as a control was investigated.Also, the total amount of biomass, consumption of sugar, strength of levy and kinetic's parameters of growth in all mediums were determined.For enriching the mediums, yeast extract and pepton were used in order of 3.5 and 7%, respectively. Fermentation process carried out during 12 houres and the temperature is maintained constant to 30 C° .Agitation was of 150 turns per minutes and ventilation fixed at 2 V.V.M .According to the results,maximum and minimum amount of biomass were 93.33 and 81.35 g/l that they related to date and whey, respectively.The consumption of sugar except whey which had the lowest level, in other cultures had no significant difference.The highest yield (0.35g/g) is observed in date but the lowest yield was 0.32 g/g in whey. Also, the baker's yeast which growed in raisin extract, had the highest value in strength of levy.
