Food Engineering
Fatemeh Karani; Javad Sargolzaei
Abstract
Introduction: The Okra belongs to the family Malvaceae with the scientific name Abelmoschus esculentus (Peyvast, 2009). The viscous property of okra is due to the thick and viscous matter in the fruit pod, called mucilage. Okra mucilage is a polysaccharide currently used in pharmaceutical industry as ...
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Introduction: The Okra belongs to the family Malvaceae with the scientific name Abelmoschus esculentus (Peyvast, 2009). The viscous property of okra is due to the thick and viscous matter in the fruit pod, called mucilage. Okra mucilage is a polysaccharide currently used in pharmaceutical industry as a hydrophilic polymer in tablet coatings (Bakre et al, 2009). Mucilage collectively contains polysaccharides, proteins, and minerals found in a plants or seeds that are more widely used in various industries, including food industry, as a stiffener in dairy products. Mucilage composed of monosaccharide polymers, amorphous and semi-transparent, and are hydrocolloids. These materials are hydrophilic molecules that can be extracted with water and form a concentrated or gel solutions. Gels are widely used in the food, pharmaceutical and non-pharmaceutical industries. The cultivation of okra in Iran is mainly occurred in tropical and subtropical regions and is found in Khuzestan, Ilam, Kermanshah, South Fars, Bushehr and Hormozgan provinces (Mozafarian, 2012). Many studies have been done on the extraction of okra mucilage and its applications in the pharmaceutical and food industries. Faroq et al. worked on the organoleptic properties of okra mucilage and concluded that okra mucilage has good flow properties and high solubility in water that can be used safely without any side effects (Farooq et al, 2013). ). Noorlaila et al studied the emulsifying property of mucilage extracted from okra (Noorlaila et al, 2014). Nazni and Vigneshwar studied the extraction and evaluation of organoleptic properties of mucilage from okra and several other plants and used ethanol and acetone to purify mucilage (Nazni et al, 2012). A study was conducted in 2018 to study the basic properties such as swelling index, emulsion stability, viscosity and antioxidant activity of okra mucilage (Fekadu Gememde et al, 2018). In a study on the use of okra mucilage in pharmacy, Ameena et al after extracting mucilage from okra and measured the physicochemical properties of mucilage, applied it in tablet formulation and many parameters such as diameter, thickness, weight change, hardness and Fragility were assessed. According to observations, low concentrations of okra mucilage can be used as a substitute for starch in tablet formulation, and also high levels of okra mucilage can be used in the drug release system as a natural substance (Ameena et al, 2010). In a study, Mishra et al presented okra mucilage as a new proposal to replace polymer materials used in various industries (Mishra et al, 2008). In 2014, the effect of okra mucilage on the release of propranolol hydrocolloid in tablets was studied. The highest hardness and lowest brittleness were observed for okra tablets (Zaharuddin et al, 2014). In this research, extraction of okra mucilage was investigated by two methods of solvent and supercritical fluid extraction. Optimization the yield and physicochemical properties of the extract obtained from both methods was also investigated. Materials and methods: Fresh okra obtained from local supermarket in Khuzestan province. Chemicals materials such as pure ethanol, acetone, chloroform, acetonitrile purchased from Merck and Sigma Aldrich. After transferring the okra fruit to the laboratory, the contaminants were removed from the plant and then rinsed thoroughly with water. The okra pods were dried at about 40 °C in a digital fan oven model 6882A. It was powdered by a German-made electric milling machine and then it passed through a 30-mesh sieve to be ready for extraction and it was weighted by laboratory scales (0.0001 precision manufactured by Cornell, Germany). In the solvent extraction process, the okra powder was weighed by a digital balanced (GR-200 model made in Japan) and transferred to 250 ml human. The solids stirred in distilled water and various amounts of solvent for 1 to 5 hours until the mucilage is completely released into the water. The solution was filtered and then adjacent to an organic solvent. Then, the filtrate was poured again into Petri dish and placed on a water bath at 45 °C to evaporate the residual solvent inside it. The residue inside the Petri dish was dried in a fan oven (Reyhan Teb Company) at 40 °C and powdered and kept at 20 °C until the day of analysis. In the supercritical extraction method, the supercritical fluid extraction machine which designed and manufactured in the laboratory of the Faculty of Engineering at Ferdowsi University of Mashhad was used. The carbon dioxide was supplied by Khakakan Co., Quchan Road, Iran in a 45 kg cylinder. Results & Discussion: Generally, according to the results of both methods of solvent extraction and supercritical fluid extraction (SFE), the extraction efficiency of mucilage at the optimal point in the solvent extraction and in the supercritical methods was 5.12% and 1.58%, respectively. Due to the less use of organic solvents in the supercritical method, this method is more environmentally friendly, which is significant in converting the laboratory method to pilot or industrial scale. Physio-chemical analysis of mucilage obtained by two methods shows that the index of swelling, moisture and ash of mucilage obtained by maceration is more than that of supercritical mucilage. By comparing the obtained values at the optimal point of both methods, the solvent method has a higher total efficiency and has been more successful. However, in the supercritical fluid method, the solvent utilization is significantly reduced. The extraction time in the supercritical fluid method is also reduced by about 50%.
Behrooz Alizadeh Behbahani; Fakhri Shahidi
Abstract
Introduction: Meat and meat products undergo chemical and microbial spoilage during production, transportation, storage and consumption. Antimicrobial edible coatings containing natural herbal extracts and essential oil possess various benefits and are currently used to design novel active biodegradable ...
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Introduction: Meat and meat products undergo chemical and microbial spoilage during production, transportation, storage and consumption. Antimicrobial edible coatings containing natural herbal extracts and essential oil possess various benefits and are currently used to design novel active biodegradable packaging. Natural polysaccharides are considered as potentially good candidates to fabricate edible coatings and provide a shelf life extender. There are no researches in the literature concerning the potential effect of Carum copticum essential oil (CCEO) enriched Scutellaria lateriflora seed mucilage (SLSM) based edible coatings on the quality and shelf life of lamb during refrigeration storage. The objective of this study was therefore to investigate the inhibitory effect of CCEO loaded SLSM edible coating towards lipid oxidation and microbial spoilage of lamb during cold storage conditions. Materials and methods: In this study, SLSM was extracted from whole seeds using hot-water extraction. Edible coating was prepared by dissolving 2 g of the extracted SLSM and 0.1 g of Tween 80 in 100 mL of sterilized distilled water. The mixture was stirred and heated for 2 h. Afterwards, CCEO was added to the SLSM solution at 0, 1, 1.5, and 2%, and the obtained solution was used as an antimicrobial coating for extending the shelf-life of lamb slices. The control and the coated lamb samples were analyzed periodically for microbiological (total viable count, psychrotrophic count, Escherichia coli, Staphylococcus aureus and fungi), chemical (peroxide value and pH), and sensory characteristics (color, odor and overall acceptability). Results and discussion: SLSM extended the microbial shelf life of lamb by 3 days, whereas SLSM + 1% CCEO, SLSM + 1.5% CCEO and SLSM + 2% CCEO resulted in a significant shelf life extension of the lamb by 6, 6, and 6 days, respectively as compared to the control samples. The results demonstrate that the EO-rich edible coating functions as an oxygen barrier and, in turn, limits the growth of most important and aerobic psychrotrophic bacteria, i.e. Pseudomonas species, which are mainly responsible for the fresh lamb spoilage under aerobic conditions. The results showed that the pH of lamb coated with SLSM and samples containing CCEO was lower than the control. The results showed that the peroxide value in the control sample increased from 0.4 to 9.7 meq oxygen/kg during 9 days of refrigerated storage. Based on the finding of this study, the use of CCEO-loaded coating manifestly lowered the meat lipid oxidation. The resultant edible coating manifestly improved the shelf life of lamb through suppressing microbial spoilage and inhibiting lipid oxidation. The coating containing 2% CCEO conferred good quality characteristics to the lamb and expanded its refrigeration shelf life.
Younes Zahedi; Hadi Mahdavian Mehr; Seyed Mohammad Ali Razavi
Abstract
Identification of a new source of hydrocolloids is of interest due to their important effects on the textural attributes of food products. The objective of this study was to investigate the extraction conditions of Plantago major L. seed mucilage using a central composite rotatable design of response ...
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Identification of a new source of hydrocolloids is of interest due to their important effects on the textural attributes of food products. The objective of this study was to investigate the extraction conditions of Plantago major L. seed mucilage using a central composite rotatable design of response surface methodology. Temperature (25–85°C), pH (3–9) and water to seed ratio (50:1-50:4) were the factors investigated. Results showed that temperature was major factor in the extraction yield, whereas water to seed ratio and pH had minor effects on the yield. The maximum and minimum yields were 18.95% (conditions: temperature= 85 °C, water to seed ratio = 31.3 and pH= 6) and 6.35% (conditions: temperature = 25 °C, water to seed ratio= 31.3 and pH= 6), respectively. The optimal conditions were obtained at the temperature of 60 °C, water to seed ratio of 48.9 and pH of 3 in which predicted value for the extraction yield was 11.84%. The rheological properties of the mucilage, extracted at the optimal conditions, were investigated as a function of concentration at three levels of 3, 4 and 5% w/v, and shear rate ranged from 14 to 300s-1. Mucilage dispersions showed non-Newtonian shear-thinning behavior at all studied concentrations. The Power law model well described the rheological behavior of the mucilage solutions with high determination coefficients (R2>0.99). The flow behavior index (n) varied in the range of 0.30 to 0.36. The consistency coefficient (k) was in the range 6.13-17.81 Pa.sn. Overall, Plantago major L. seed mucilage could be attended as a new beneficial source for use as a food thickening agent.
