Mohammad Ganjeh; Seyed Mahdi Jafari; Mehrdad Niakosari; Ali-Mohammad Tamaddon; Yahya Maghsoudlou
Abstract
Introduction: In recent years, production of nutraceuticals by adding bioactive compounds and nutrients has been grown substantially. These compounds are generally sensitive to environmental or gastrointestinal conditions and their bioavailability is limited due to destructive reactions. One of the common ...
Read More
Introduction: In recent years, production of nutraceuticals by adding bioactive compounds and nutrients has been grown substantially. These compounds are generally sensitive to environmental or gastrointestinal conditions and their bioavailability is limited due to destructive reactions. One of the common methods to reduce or prevent these kind of problems, is microencapsulation of valuable compounds in some materials which can protect them against environmental conditions, and enabling them to controlled release from trapped compounds at specific time and place. Orange peel oil, contains some important bioactive compounds such as limonene that is used in a variety of beverages, foods, cosmetics, pharmaceuticals and chemicals. D-limonene is the main constituent of orange peel oil, because it makes an 80-95% fraction of the orange peel oil volatile compounds, depending on fruit variety. In addition to its technological characteristics (flavor), D limonene can stop or delay the initiation of cancer. It can also be used as a safe alternative to antimicrobial compounds. Nevertheless, technological limitations (hydrophobic structure, high reactivity, sensitivity to oxidation and volatility) often avoid suitable use of this compound as a dietary supplement. Polysaccharides are among of the basic materials which are applied more in this field. Several factors such as cheap and easy access, having active groups interacting with hydrophobic and hydrophilic compounds, biodegradation, biocompatibility and relatively high thermal resistance, have turned them to be superior to lipid and protein carriers. One of the most important polysaccharide compounds existing in nature, is starch. It can be used as a carrier in encapsulation processes with different purposes, having advantages such as inexpensive, non-toxic, capable of recrystallization, the ability to form film and complex and resistant to various degrees of enzymatic hydrolysis. Spatial configuration of amylose is changed in the presence of ligands such as iodine and linear alcohols, resulting in a left-handed helix which can trap ligands within or between curvatures derived from glucose connections. One of the major structures which is created in the interaction of amylose and lipophilic substances, is known as V-amylose structure. V-amylose is a left-handed helix with an inner hole which ligands can be placed within it. The aim of this study was to determine the effectiveness of amylose in nanoencapsulation of limonene as a bioactive compound with desirable sensory characteristics using a thermo-mechanical stress.
Materials and methods: Based on the analysis of pure limonene samples (Sigma-Aldrich) as well as samples used in this study, more than 92% of examined sample comprised of D-limonene. In order to prepare amylose nanoparticles containing limonene, 0.1 molar solution of potassium hydroxide (Merck, Germany) was prepared in deionized water and then high amylose corn starch (HACS) (Sigma-Aldrich (St. Louis, MO, USA) with 70% amylose was added to it in the ratios of 2: 4% while stirring continuously for 30 minutes at 80°C. Limonene was then used in the ratios of 5: 10% of HACS was added to the suspension and stirring continued for 1 minute. Initial suspension has been processed by using ultrasound system (Model UP100- Hescheler Company, Germany) with 100 W power and frequency of 30 kHz for 9 and 18 minutes. The viscosity of amylose suspensions containing nanoparticles with different formulations was measured by using a capillary viscometer (Schott-Gerate-Capillary-Viscometer-525-00- Germany). Size and zeta potential was measured by using dynamic light scattering (DLS) and Nanotrac Flex In-situ Particle Size Analyzer devices and Microtrac ZETA-check determined. The morphology of nanoparticles was studied using a scanning electron microscopy (TESCAN-Vega3- Czech Republic). Microencapsulation efficiency and loading efficiency were determined by using spectrophotometry.
Results and Discussion: In all formulations, particle sizewere less than 50 nm. Starch granules were exposed to cavitation stress by applying the ultrasonic process .The constant formation of bubbles creates a mechanical impact with high energy on starch granules during bursting. Fast impingement of fluid to granule surfaces, hitting particles to each other as well as resistant of the granules against fluid stream cause breaking of starch particles into nanoparticle scales. The highest amount of zeta potential was related to the sample which had the highest starch and limonene concentration. Amylose concentration had the main effect on zeta potential changes. Electrostatic charges can be the main reasons for the higher zeta potential in samples with 4% amylose concentration. More increasing in surface active agents of amylose, namely ionized hydroxyl groups of glucose molecules leads to increasing in surface charge, and results in zeta potential. The most impact on solutions viscosity is related to amylose concentration. Generally, increasing the amylose concentration leads to increasing the solution viscosity, in other side, with ultrasound treatment, the amount of this index was reduced and the solution became more fluent. Microencapsulation and loading efficiency values ranged between 28-82% and 0.38-1.63% respectively. The limonene concentration had the most impact on the efficiency in various formulations. At similar treatments with %4 amylose concentration and 9 min sonication period, by increasing the amount of limonene from %5 to 10, microencapsulation and loading efficiency were increased from %31 to %82 (%62 growth) and from 0.52 to 1.41 (%63 growth) respectively.
Mohammad Ganjeh; Seyed Mahdi Jafari; Mohammad Hoseinnejad
Abstract
Introduction: Yogurt is the most frequently consumed fermented milk product with a positive impact on human health due to its high nutritional value. Characteristics such as acidity, amount of free fatty acids with sensory characteristics and nutritional properties of yogurt are very important. Food ...
Read More
Introduction: Yogurt is the most frequently consumed fermented milk product with a positive impact on human health due to its high nutritional value. Characteristics such as acidity, amount of free fatty acids with sensory characteristics and nutritional properties of yogurt are very important. Food fortification is defined as addition of one or more essential nutrients at levels higher than naturally presence in food products. The World Health Organization estimates that at least 1 of every 5 people in the world suffer from lack of iodine, zinc, iron, folic acid, calcium, vitamin A and B. The aim of this study was to evaluate the changes in physicochemical, textural and sensory properties of iron and zinc enriched yogurt during the shelf-life period and to assess the extent and the effect of these supplements on these properties.
Materials and methods: To perform enrichment, milk was divided into seven parts: 3 containers for fortification with iron, 3 containers for fortification with zinc and 1 container as the control sample. Fortification with iron and zinc was performed by concentrations of 20, 40 and 60 mg per kg of milk (according to the daily requirement of iron and zinc). The samples were then transferred into the container of 100 grams which were incubated at 45 °C, and after reaching the pH of 4.4 to 4.5, they were transferred to cold storage at 4 °C. To investigate the effect of enriching on the produced yogurt properties, the samples were evaluated after a period of one, seven and fourteen days. The syneresis of yogurt samples was determined by Salvador and Fiszman (2004) method, with slight modification. Water holding capacity was determined by centrifuge (Hettich Universal 320R - Germany) as reported by Sahin et al (2008) with slight modification. The acidity of the yogurt samples was measured by Kim and Lee (2002) method based on the percentage of lactic acid. Sensory characteristics of our samples in terms of taste, odor, color and texture and overall acceptability were evaluated by 12 Panelists (6 males, 6 females, 45- 21 years) by using a five-point hedonic test. Texture analysis was performed using Texture Analyzer (Brookfield Model CT3 Texture Analyzer – USA) based on Supavititpatana et al (2008) method.
Results & discussion: Syneresis of product decreased from 0.24 to zero in yogurt samples containing iron and from 1.20 to 0.81% in zinc treatments. Increasing the storage time in the presence of iron causes a sharp decrease in the amount of the syneresis up to zero. The main reasons for syneresis in fermented products include high incineration temperature, low total solids and inadequate storage temperature. The water holding capacity of the product was shown a relatively increase over time and the highest amount was observed in the treatments containing high concentrations of iron during the early days of storage, while at the same high concentrations in the final days of storage, the lowest water holding capacity was observed, which could be due to the adverse effect of the storage time on this factor. The viscosity increased over time, and the rate of increase in the early days was far higher than the final days (in both iron and zinc treatments). In iron and zinc treatments respectively, water holding capacity increased from 50.08 to 55.50, and 43.57 to 55.47 % and viscosity from 855.55 to 961.11, and 677.78 to 833.30 mPa s. By analyzing data obtained from texture analyzer, important properties such as firmness and springiness increased and the lowest cohesiveness and the highest adhesiveness were observed in the middle of storage time. Both iron and zinc treatments increased the hardness of the product compared to the control samples and the amount of this increase in iron containing yogurt samples was slightly higher than that of zinc. In both treatments, there was a significant decrease in the product adhesion force compared to the control sample. In contrast, the highest continuity of product was observed in the middle days of the storage period.The highest levels of flavor were detected on the seventh day of storage, and changes in the zinc and iron content of the products were almost ineffective in the desirability or taste loss, and only control samples were evaluated with a little higher flavor than other treatments. Sensory properties were not significantly different (P
Elham Sadati gol afshani; Seyed Mahdi Jafari; Mahdi Kashani-Nejad; Shahram Beiraghi-Toosi; Mohammad Ganjeh
Abstract
Introduction: Osmotic dehydration involves the partial removal of water by direct contact of a product with a hypertonic medium such as high concentration of sugar, salt or sugar-salt solutions. In this process, food pieces are immersed in a hypertonic solution. The natural membrane of food cells acts ...
Read More
Introduction: Osmotic dehydration involves the partial removal of water by direct contact of a product with a hypertonic medium such as high concentration of sugar, salt or sugar-salt solutions. In this process, food pieces are immersed in a hypertonic solution. The natural membrane of food cells acts as a semipermeable layer so the water moves across the membrane from an area of high water potential (low solute concentration) to an area of low water potential (high solute concentration), meaning the driving force for water removal is the concentration gradient between the solution and the intracellular fluid. During osmotic dehydration, osmotic solute is absorbed by food materials and has undesirable effects on water removal, nutritional and organoleptic properties. Use of coating improves the osmotic processing. Best factor for evaluation of coating material is performance ratio (WL/SG). So a coating should reduce solid uptake without negative effects on water removal.
Materials and methods: The apples (Golden delicious) used in this study were purchased from a local market in Mashhad (Iran) and stored at 4-6°C before processing. The sucrose (99.9%, Fariman sugar company, Iran), carrageenan (kappa type, Negin Khorak Pars Company, Iran), carboxy methyl cellulose (sandros, Japan) and calcium chloride (Dr. Mojallali Lab., Iran) were also used. In this work, apple cubes were single and double coated in three concentrations (0.5, 1 and 1.5% w/w) of carboxy methyl cellulose (CMC) and carrageenan solution and dehydrated osmotically in different concentrations (30, 45 and 60˚ BX) of sucrose solutions.
Results and Discussion: The results of this study indicated that increasing coating solution concentration from 0.5% to 1.5% decreased water loss. Also the water loss increased when the number of coating layers and the concentration of osmotic solution increased (from 30 to 60 ˚ BX). Generally, water loss and solids uptake in the samples coated with carrageenan was higher and lower than their CMC counterparts, respectively. The solids uptake in the samples coated with CMC increased by increasing the number of layers, osmotic solution concentration (from 30 to 60˚BX) and coating solution concentration (from 0.5 to 1.5%). The solids uptake increased and decreased with increase in layer number and coating solution concentration (from 0.5% to 1.5%), respectively. Increasing the osmotic solution concentration up to 45 ˚ BX increased solids uptake but, more increasingly did not have a significant effect on it. Finally, it cannot be said strictly that one coating type would facilitate osmotic process or not. It depends on various process factors. Among the 36 treatments studied in this research, the single coated samples with 1% carrageenan treated in 60 ˚ BX sucrose solution and the single and double coated samples with 0.5% CMC treated in 45 ˚ BX sucrose solution were the best, as they had 50% higher performance ratio than control (uncoated) sample.
