Food Chemistry
Ahmad Ehtiati; Massoumeh Mehraban Sangatash; Reza Karazhyan; Zahra Nazari; Farzad Sadeghi
Abstract
Introduction: Shortening is an important ingredient of bakery products, especially the ones with less developed gluten network like cakes and cookies . Shortening thermo-rheological properties are related to the presence of high levels of saturated fatty acids which have the capability of making ...
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Introduction: Shortening is an important ingredient of bakery products, especially the ones with less developed gluten network like cakes and cookies . Shortening thermo-rheological properties are related to the presence of high levels of saturated fatty acids which have the capability of making crystals at room temperature which melt during baking. Consumption of high saturated fatty acids increases the risk of coronary disease. Moreover, hydrogenation is a usual technique for elevating the saturated fatty acid content of vegetable oils. Lowering the saturated fatty acid content of a shortening results in the shortening with less functionality. Transition of an oil physical properties to those of a semi-solid structure can be done using low- or non-digestible oil gelators called oleogelation. Ethyl cellulose is a polymer with oil gelation capabilities at low concentrations. However, its oleogels are firm and brittle, so some low-molecular-weight gelators can improve its texture and increase its plasticity to mimmic commercial shortening functionality. In this study, the functionality of an oleogel based on ethyl cellulose, stearyl alcohol, stearic acid and sorbitan monostearate was evaluated as commercial shortening substitute in cake formulation. Materials and Methods: Based on previous studies and preliminary experiments, an optimized oleogel formulation was prepared as shortening, composed of ethyl cellulose (6.4%), stearyl alcohol:stearic acid (70:30) (7.5%), sorbitan monostearate (0.1%) and canola/soy mixture oil (75:25 ratio) (86%).The gel was formed by heating up the mixture to 150 °C for the complete solvation of the gelator compounds and gradual cooling to room temperature. In the next step, commercial shortening was substituted with the oleogel shortening at 0, 25,50, 75 and 100% in the cake formulation. Moisture content, water activity, specific volume, crust color, Lab color space indices based on image processing, porosity based on crumb image analysis, TPA parameters and sensory attributes were determined and compared using one-way analysis of variance and LSD mean comparison test. Results & Discussion: The results showed that there was no significant difference in the moisture content, water activity and specific volume of the cakes prepared with the oleogel shortening with the one prepared with commercial shortening. This reveals that the oleogel shortening functionality was acceptable compared with commercial shortening. In terms of crust color, there was no significant difference in the lightness index (L*) and red-green range (a*) indicators between different samples and only in the yellow-blue range (b*) index, the cake with 100% substitution showed a lower value than the control. For the porosity index, there was no significant difference between the five samples, proving the oleogel shortening can induce sufficient air bubbles generated during batter mixing and its preserving effect during baking. Examining the texture of the cake samples showed that the texture hardness and springiness indices decreased with a rise in the level of commercial shortening substitution, while the cohesiveness index did not differ significantly. The latter indicated that the oleogel shortening effectively shortened the gluten network; thus, it can be said that the same commercial shortening functionality is attainable using less oleogel shortening content. Furthermore, as the percentage of the commercial shortening substitutes increased, due to texture softening, the chewing energy of the samples decreased resulting in a better mouthfeel. Finally, sensory evaluation of the cake samples did not show a significant difference in taste, texture, appearance, color and overall acceptance based on scores obtained from ten untrained evaluators. In conclusion, the use of oleogel shortening instead of commercial shortening with high saturated fatty acid content in cake formulation not only can result in a cake with acceptable properties at 50% replacement level, but also can replace commercial shortening even up to 100%.The latter just lead to a softer texture. Optimization of the cake formulation based on the oleogel shortening would specifically result in a cake with better properties, while it has significantly lower saturated fatty acid content and nearly zero trans fatty acids.
Elham Mahdian; Reza Karazhyan
Abstract
A nutraceutical food may provide expanded utility beyond its nutritional benefit. These benefits are commonly attributed to the active components of the food. Fruit by-products are rich source of dietary fibers that have beneficial effects on human health. Also they can improve the growth and viability ...
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A nutraceutical food may provide expanded utility beyond its nutritional benefit. These benefits are commonly attributed to the active components of the food. Fruit by-products are rich source of dietary fibers that have beneficial effects on human health. Also they can improve the growth and viability of probiotics in food matrix and therefore suitable to produce synbiotic food products. In this study, the effect of adding fiber obtained from apple, banana and mango peels at levels of 0.5, 1 and 1.5% on physicochemical and sensory features and the viability of Lactobacillus casei LC-01 in ice cream during 60 days storage at -18°C was investigated. Based on the results, all ice cream mixes were pseudoplastic fluids. The values of flow behavior index decreased and consistency coefficients increased by increasing the level of all mentioned fibers. The pH and specific gravity of samples containing banana and mango fibers were lower than control and sample with apple fiber. Using fibers had no significant effects on overrun values, whereas viscosity and melting resistance of ice cream samples increased with increasing fiber amounts. The most reduction in Lactobacillus casei LC-01 count after freezing and during storage period was associated to control sample and adding all types of examined fibers improved probiotic viability. Minimum cell reduction after freezing and during storage period occurred in sample containing 1.5% mango fiber with 0.03 and 0.48 log cycle respectively. Sensory properties of samples containing apple fiber were good and comparable with control sample.
Samaneh Rezaei; Mohammad Bagher Habibi Najafi; Fereshteh Hosseini; Reza Karazhyan
Abstract
Introduction: Nowadays, with the increasing awareness of the side effects of synthetic additives, consumer’s demand for colorants from natural sources has been increased. Annatto is an allowed natural colorant used in food industries, textiles, cosmetics and pharmaceutical products. The colorant is ...
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Introduction: Nowadays, with the increasing awareness of the side effects of synthetic additives, consumer’s demand for colorants from natural sources has been increased. Annatto is an allowed natural colorant used in food industries, textiles, cosmetics and pharmaceutical products. The colorant is extracted from the seeds, which are covered by a red, resinous pericarp containing the pigments. The main pigment is bixin (methyl hydrogen 9′-cis-6, 6′-diapocarotene-6, 6′-dioate) which is responsible for the orange red color in the seeds (80% of total carotenoids). Smaller amounts of norbixin are also presented. Bioactive compounds like bixin and phenolic compounds reduce the risks of various chronic disorders, such as cancer, inflammation, cardiovascular, hypercholesterolemia, diabetes, and cataracts (Boschetto, et al., 2014; Somacal et al., 2015; Ezuruike & Prieto, 2014). Moreover many studies have proven antimicrobial activity of annatto extracts (leaves, capsules, seeds…) against several food spoilage and pathogenic bacteria such as Staphylococcus aureus, Escherichia coli and Bacillus subtilis, as well as few fungi such as Candida utilis, and Aspergillus niger. Annatto is a permitted natural food coloring with antioxidant properties, high therapeutic potential and antimicrobial effects. The aim of this study was to evaluate antimold activity of annatto natural dye on 3 important food pathogenic and spoilage molds, Aspergillus niger,Neurospora sitophila and Rhizopus stolonifer.
Material and Methods: Annatto dye was extracted by maceration method and after filtration it was dried by a vacuum oven. Anti-mold activity was evaluated by well diffusion and disk diffusion methods in 1 to 10 percent concentrations of acetone extract of annatto and minimum inhibitory concentration (MIC) was determined using agar dilution method at 48 and 72 h after incubation at 25 °C.
Results and Discussion: The results indicated promising anti-mold activity. The highest mean zones of inhibition in all concentrations were obtained for Aspergillus niger, Neurospora sitophila and Rhizopus stolonifer, respectively. This difference might be due to the more resistance and rapid growth of Rhizopus stolonifer and Neurospora sitophila compared to Aspergillus niger. No inhibitory effect was observed in the concentrations below than 1%, this result is in consistent with Irobi, et al., (1996) findings that proved annatto's organic extract has a weak effect on Aspergillus niger at low concentration (5 mg/ml).In all concentrations, Aspergillus niger showed the highest inhibition zone and the most sensitivity to annatto extract found at Aspergillus niger, Neurospora sitophila and Rhizopus stolonifer, respectively. Disk diffusion method was inefficient to inhibit mold growth. Minimum inhibitory concentration of annatto dye against Aspergillus niger and Neurospora sitophila was determined 6 percent while Rhizopus stolonifer showed 7 percent. According to the results annatto dye was effective to inhibit growth of Aspergillus niger, Neurospora sitophila and Rhizopus stolonifer. Therefore it can be concluded that annatto dye could be used as a functional and inhibitory agent against mold growth in the foods that are susceptible to mold spoilage (e.g. bakery goods).
