Food Technology
Ali Kashani; Maryam Hasani; Leila Nateghi; Mohammad javad Asadolahzadeh; Parvin Kashani
Abstract
Introduction: Nowaday, the demand for low calorie food based and keeping primary features including texture and taste is increasing. Jelly is one of low calorie products produced from fruits and other components, and its consumption is increasing for human health. Jelly is semi-solid and transparent ...
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Introduction: Nowaday, the demand for low calorie food based and keeping primary features including texture and taste is increasing. Jelly is one of low calorie products produced from fruits and other components, and its consumption is increasing for human health. Jelly is semi-solid and transparent product that prepared with the use of sugar or juice and pectin or gelatin and flavor and color may also be added. Potato peels contain valuable substances such as pectin. Using potato peels to produce pectin with appropriate properties can solve the environmental issue resulting from these wastes in addition to make value added product. Pectin is a complex polysaccharide that is found in the wall of early plant texture and in the intercellular layer. Pectin contains a group of rich polysaccharides of galacturonic acid units with lower amounts of different sugars (Baiano, 2014). Two commercial forms of pectin are available: high-methoxyl and low-methoxyl pectin (high ester and low ester pectin). High-ester pectin forms a gel in a solutions containing high soluble solids and acidic systems, whereas low-ester pectins form more gel at wider pH and range of solids content but they do require divalent cations to form the gel (Kratchanova et al., 2012). In the food industry, pectin is used as a jelly-making agent, especially in the production of jellies and jams. Pectin is also used in fillers, medicine, pastries, bakery products and also as a stabilizer in juices and beverages, as well as in dietary fiber (Sharma, 2006). Pectin also has therapeutic benefits such as lowering blood cholesterol levels, removing heavy metal ions from the body, stabilizing blood pressure and facilitating intestinal activity (Ptichkina et al., 2008). Temperature, pH, and acid extraction time are the most important factors affecting the extraction yield and quality of produced pectin (Yapo et al., 2007). Currently, almost all commercial pectins are produced from citrus or apple peels, both of which are juices by-products (Thirugnanasambandham et al., 2014). Therefore, the main objective of this study was to optimize the conditions of extraction of pectin from potato peel by response surface methodology and to compare the physicochemical properties of Jelly produced from potato peel under optimum conditions with Jelly produced from apple and citrus Material and methods: Potato of Granola variety was purchased from the local market in Ardebil. The chemicals used for the tests include: citric acid, sodium hydroxide, phenolphthalein, and Calcium chloride were purchased from Merck Company (Germany). The method of Hoseeni et al (2017) was used for jelly production with slight modification as follows. In the First step,0.5 and 1% pectin extracted from potato peelings, 30 % Sugar, 0.014 % Cherry edible color and 0.75 % Cherry essential oil were mixed then 100 CC Boiling water was added to the mixture and mixed again. After the sugar was completely dissolved, 15, 30, and 45 mg of calcium chloride was added per gram of pectin. The pH of the samples was regulated by citric acid solution on 2.5 and 4. The heating of the samples was continued until the brix of the treated treatments was set to 42. The prepared samples were kept at room temperature for half an hour. The treatments were then refrigerated for 2 to 3 hours to complete the jelly closing process. For this purpose some jelly characteristics such as texture properties, physico-chemical (pH, acidity, brix, moisture and Drainage) and sensory properties of samples were investigated using five point hedonic scale. A one-way analysis of variance and Duncan test (P≤ 0.05) in three replications were used to establish the significance of differences in the experimental data. The results were analyzed using the Minitab version 16. Results & Discussion: Results showed that by increasing calcium chloride, pH and Pectin concentration had a significant effect on increasing the hardness of the gel and the strength needed to make the gel brittle (P≤0.05).The highest hardness of the gel in pectin emulsion extracted from potato peel was 30.0959 N and highest force required to break the gel was 27.3431 N in the most severe extraction conditions at Calcium chloride 35.2286 mg/g, Pectin concentration 1% and pH 4. Results of physico-chemical properties showed that there was no significant difference between pH, acidity, brix and moisture of jelly made from apple pectin and citrus and apple commercial pectin. The results of the syneresis showed that the syneresis by the jelly of potato pectin is not similar with jelly from apple pectin and citrus and apple commercial pectin significantly different. Also Results of sensory properties showed that it was no significant difference between jelly from apple pectin and citrus and apple commercial pectin. The results of this study showed that by optimizing the production conditions, potato pectin can be used in jelly formulation and jelly can be produced with desirable and comparable quality compared to the commercial pectins
Shadi Basiri; Fakhri Shahidi
Abstract
Introduction: Morus Alba, known as white mulberry, is a short-lived, fast-growing and small to medium sized mulberry tree, which grows to 10–20 meters tall. The species is native to northern China, and is widely cultivated and naturalized elsewhere. The fruit is 1–2.5 cm long in the species in the ...
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Introduction: Morus Alba, known as white mulberry, is a short-lived, fast-growing and small to medium sized mulberry tree, which grows to 10–20 meters tall. The species is native to northern China, and is widely cultivated and naturalized elsewhere. The fruit is 1–2.5 cm long in the species in the wild, it is deep purple, but in many cultivated plants it varies from white to pink, being sweet and bland. The fruits are also eaten, often dried or made into wine or vinegar. In traditional Chinese medicine, the fruit is used to treat prematurely grey hair, to tonify the blood, and treat constipation and diabetes. White mulberry is a fruit with high nutritional quality. The shelf life of mulberry is short due to its high moisture content. Dried mulberry and its molasses are popular products from mulberry fruit. Hydrocolloids are used in fruit snacks formulations to create novel texture, increase stability for their water-holding capacity, improve texture and have an impact on flavor release and other structural and sensory properties in the respective products. Hydrocolloids are also widely used in the food industry as thickeners, stabilizers and gelling agents in various products including ice cream, sauces, jellies and pastille products. Guar gam is kind of long-chain galacto-mannan with high molecular weight, obtained from endosperm of guar plant. This type of synergistic behavior among polysaccharides is commercially valuable, because it creates a novel texture and a more desirable structure. The aim of this research is to produce mulberry pastille as a novel and value added product with long shelf life. Beside it can be introduced as a healthy snack replacing sugar. Materials and methods: The materials include mulberry puree, hydrocolloids (Gelatin and guar) and citric acid. Berries were collected from the gardens around Mashhad (Iran). Guar was purchased from Sigma Chemical Company, citric acid was purchased from Merk Chemical Company, Germany. Gelatin (0, 1, and 2 %) and Guar (0, 0.5, and 1 %) were used for pastille formulations. To produce fruit pastille based on mulberry puree, the prepared puree was mixed into hydrocolloids. After measure pH and moderating to PH = 4.3 by adding acid citric in 40 % concentration and controlling the Brix degree to constant Brix of 45, the mixture was prepared. Then the prepared mixture was poured into a network framework of steel origin in the cavities with 1.2×1/2 and the molds were hold in the refrigerator for 2 hours with 4°C to fasten the gel. The obtained gel was taken out of the mold cavities and placed in a glass plate. The samples were then dried at 70° C in a hot air drier with airflow rate of 1.5 m/s for 6 hours. The samples were evicted every 30 minutes. Parameters such as color, sensory and textural characteristics of samples were investigated. Statistical design was 2 factors factorial with three replicates adopted completely randomized design. Results and Discussion: The results of texture evaluation showed that increasing guar gum improves the cohesion, elasticity and chewiness of the samples, while their adhesion were decreases. Conclusion: Mulberry pastille including 1% Guar and 1% Gelatin having the lowest amount of firmness, adhesion, chewiness and suitable color characteristics, was determined as the best formulation among the other investigated samples.
Mohamad Mehdi Heydari; Seyed Mehdi Nassiri
Abstract
Introduction: Given that fruit drying is one of the best economical storing methods, in the present study attempt has been made to apply a commercial drying method, namely passing warm air through fruit in a cabinet drier, to pinpoint the change in textural properties of pear fruit during drying at different ...
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Introduction: Given that fruit drying is one of the best economical storing methods, in the present study attempt has been made to apply a commercial drying method, namely passing warm air through fruit in a cabinet drier, to pinpoint the change in textural properties of pear fruit during drying at different inlet air temperature and velocity levels. The outcomes of the study can be used for optimizing the drier operation during drying (intelligent driers) to keep suitable textural properties of final product for those who use sweet dried fruit as sweetener due to diabetic issues.Materials and method: Pear fruits, Shah Miveh cultivar, were collected form a garden near Isfahan city and carried to the laboratory carefully. Experimental samples with 2×2.5×2.5 cubic centimeter dimension were prepared from upper part of pear fruits. A conventional cabinet drier was used for drying the pear cubes with adjustable inlet drying air temperature and velocity. Air temperature and velocity were adjusted at three levels of 40, 50 and 60 oC, and 0.5, 1 and 1.5 m/s, respectively. Initial moisture content was measured by gravimetric methods and samples weight loss measured during drying by an online system comprising hooked type balance with ±0.001 accuracy. Dried samples were then subjected to texture profile analysis (TPA) with Instron (Santam-STM 20). Two-bite test was performed with 20 mm diameter aluminum probe, at 1 mm/s speed rate for 5 mm deformation. Textural properties of samples such as hardness, cohesiveness, adhesiveness, springiness and chewiness were drawn from force-time curve. Textural properties were measured at five sample moisture contents of 82, 66, 51, 35 and 20 percent (w.b.). Data were analyzed according to the factorial experiments based on completely randomized design by SPSS software (version 16), and the means were compared by Duncan multiple range test at 5 percent of significance. Results and Discussion: Mean comparison of drying time significantly affected by air temperature and velocity, and the effect of temperature was more than air velocity. Results revealed that textural properties of samples have changed during drying process and these changes were related to drying conditions. Hardness decreased exponentially and adhesiveness decreased linearly as fruits were being dried, whereas springiness and cohesiveness increased linearly. Chewiness followed a parabolic trend, reached to the peak in the range of 40 to 50 % moisture content levels (wet basis). ANOVA showed that drying air temperature had significant influence on hardness, springiness and chewiness, while its influence on adhesiveness and cohesiveness was not significant. Moreover, it was found that air drying velocity affected all aforementioned properties. Having considered the results of dried pear chewiness, the minimum chewiness (0.46 J) took place at air drying temperature of 40 ˚С and velocity of 1m/s, and therefore it is recommended as the best drying condition. Drying time period at this condition was measured nearly 33.5 hours, which was approximately 24 hours more than the shortest one in the drying condition of 60˚С and 1.5 m/s and 6.5 hours lower than the longest one in drying condition of 40˚С and 0.5 m/s.
