Homa Mahpour; Toktam Mostaghim; Shahla Shahriari
Abstract
Introduction: Dairy products fortification especially ice cream is one of the most important goals and priorities of today's humanbeing to produce health food products. Protein isolate is one of the compounds used to produce health products.The aim of this study was to produce ice cream with new features ...
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Introduction: Dairy products fortification especially ice cream is one of the most important goals and priorities of today's humanbeing to produce health food products. Protein isolate is one of the compounds used to produce health products.The aim of this study was to produce ice cream with new features based on a functional material by partially replacing dry matter with wheat germ protein isolate. Materials and Methods: In present research wheat germ protein isolate with 1%, 3% and 5% was extracted and added to ice cream. In the first step, protein isolate was evaluated by tests of moisture content, fat percentage, acid insoluble ash, particle size and flour grain size. In the next step, protein isolate of wheat germ by 1, 3 and 5 percent was added to ice cream mix and its effects on rheological and texture properties, color, physico-chemical and sensory parameters of ice cream were evaluated. Results and discussion: The results showed that the moisture, fat and acid insoluble ash of protein isolate were 8.41±0.42, 11.34±0.44 and 3.57±0.23 respectively. The particle size and flour grain size was 282±0.01. Laboratory data showed that by increasing protein isolate replacement, the viscosity, melting resistance and volumizing index were reduced significantly. Whereas, texture, hardness and adhesion parameters, density, particle size and diameter, specific distribution and surface area, and yellowness and redness indices were significantly increased. All the laboratory results and sensory evaluation of the samples revealed that the ice cream sample with 1 percent of wheat germ protein isolate was a preferred and optimized sample.
Sahar Sabahi; Seyed Ali Mortazavi; Mohammad Reza Nassiri; Arash Ghazvini; Fakhri Shahidi
Abstract
Introduction: Immunoglobin Y (IgY) or egg yolk antibodies have captured attention as substitutes for antibiotics against the presence of disease-causing organisms (Thomsen et al., 2016; Li et al., 2015; Pereira et al., 2019). Compared to mammalian IgG, IgY has several advantages including high yield, ...
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Introduction: Immunoglobin Y (IgY) or egg yolk antibodies have captured attention as substitutes for antibiotics against the presence of disease-causing organisms (Thomsen et al., 2016; Li et al., 2015; Pereira et al., 2019). Compared to mammalian IgG, IgY has several advantages including high yield, cost-effectiveness, and convenience (Li et al., 2015). It has been reported that the use of IgY against Helicobacter pylori can be particularly useful for prevention and treatment of diseases (Najdi et al., 2016). The growth inhibitory effect of IgY antibody is one of its crucial features (Alfarouk et al., 2019), meaning that IgY antibody could be consumed daily with no health risks. Therefore, daily consumption of IgY requires a suitable host. The ice cream is the best choice for this proposed, because this product is maintained at -18 C and ice cream composition has positive effect on the function of IgY. Therefore, we develop a new product for the prevention and treatment of Helicobacter pylori. Material and Methods: The Mueller-Hinton media was used for H. pylori growth. Then, 109 colonies of bacterium were inactivated by formaldehyde methods. The 3 white leghorn chickens (Animal Science Department of Ferdowsi University of Mashhad) of 16 weeks old were immunized by H. pylori and Freund’s complete adjuvant with an equal volume. The reminder immunization was done two weeks later and using of Freund’s incomplete adjuvant for stage 2. One week after the chickens received their last injection, their eggs were collected on a daily basis for eight weeks, labeled and kept at 4 °C (Pauly et al., 2011). Extraction and purification of IgY antibody from egg yolk was done using polyethylene glycol 6000 (PEG 6000) powder (Merck, Germany) according to Polson’s method (Pauly et al., 2011). The IgY production wasverified by the SDS-PAGE and Bradford methods. The specific activity of IgY antibody against H. pylori was examined by ELISA. The absorbance of each well was measured at 492 nm (Nasiri et al., 2016). The egg yolk ice cream preparation contains IgY was prepared according to the method of Herald et al (2008). For estimation of IgY shelf life in ice cream, the residual activity of IgY after freezing was measured by ELISA. The Sensory evaluation of the egg yolk ice creams was conducted by 5-point hedonic scale through surveys to assess consumers’ level of acceptance. Results and Discussion: The purification of IgY using the SDS-PAGE method was verified correctly and the size of heavy and light chains of IgY was estimated about 65 and 27 kDa. The IgY yield in samples was 11.46 mg/ml, therefore, the high purity and yield of IgY, it could be effectively used as an ideal antibody in the food industry. The purification of IgY from egg yolk by PEG method is remarkably cost effective. The ELISA assay indicated binding of IgY to H. pylori antigen that was fixed on plates. Also, the results revealed significant differences between the control and treatment groups (P-value <0.001). The shelf life of IgY in ice cream showed that this product could be most certainly used as bio-food. ELISA analysis confirmed that IgY could remain effective in ice cream for 3 months. The activity of IgY during this period decreased about 6%, which is insignificant. The sensory features of ice cream using hedonic scale revealed that this product could be suitable for marketing, as no significant difference was found between egg yolk and vanilla ice creams. Ice cream is considered as the best candidate for production of IgY bio-foods, as it possesses the features needed to protect IgY and to increase efficiency of IgY activity. The optimum temperature for protection of ice cream was -18 °C that is utterly suitable for IgY protection. Furthermore, ice cream is consumed while cold and studies showed that IgY can remain active at temperatures of up to 80 °C and pasteurization process had no effect on IgY activity (Horie et al., 2004). Jaradat et al (2000) reported that, IgY activity was inhibited in presence of carbohydrates (sucrose, lactose and trehalose). Therefore, here, we used freeze dried egg yolk to protect IgY. Consequently, ice-cream is an ideal candidate for transferring antibodies into human body, as the particular composition of ice cream can properly protect IgY antibodies.
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.
Seyed Mohammad Ali Razavi; Mostafa Mazaheri Tehrani; Bahareh Emadzadeh
Abstract
Introduction: Recently, consumers have directed their interest towards low fat products as they associated them with a reduced risk of well-known health problems such as obesity and coronary heart diseases. Fat is a multifunctional ingredient in ice cream system. Thus, in attempts to provide desirable ...
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Introduction: Recently, consumers have directed their interest towards low fat products as they associated them with a reduced risk of well-known health problems such as obesity and coronary heart diseases. Fat is a multifunctional ingredient in ice cream system. Thus, in attempts to provide desirable flavor and physical characteristics of full fat ice cream, manufactures looking for fat replacers (Drake et al. 1999). Hydrocolloids have functionalities such as thickening, gelling, fat replacing, which allow them to use in different industries (Roller and Jones, 1996; Williams and Phillips, 2000). Guar gum is used as a stabilizer in ice cream and provides smoothness in texture, retards ice crystal growth, and increases freeze-thaw stability (Wielinga, 2000). The rheological properties and potential of basil seed gum (Rayhan) as a novel stabilizer for structure formation and reducer for ice recrystallization in regular ice cream have been recently investigated (Hosseini-Parvar, 1388; Bahram-Parvar, 1391). In this research, the physicalproperties of light (5% fat) and low fat (2.5% fat) ice creams as a result of replacement of milk fat by guar gum (as a commercial hydrocolloid), basil seed gum (as a novel hydrocolloid) and their blend (50:50) at different concentrations were investigated and compared to those of control sample (10% fat). Materials and methods:The ice cream formulations were prepared based on the following composition: 2.5% (L), or 5% (R) or 10% (B) milk fat, 11% MSNF, 15% sugar, 0.1% vanilla, 0.15% emulsifierand 0.35%, 0.45%, 0.50% or 0.55% selected gums (guar gum, basil seed gum or blend (50:50) of them). Liquid materials including milk and cream were mixed together and warmed up to 50˚C. After that, the pre-weighed and mixed dry ingredients were dispersed into them, under agitation. The mixes were pasteurized at 80˚C for 25 s, homogenized at 23000 rpm for 2 min, cooled rapidly to 5˚C and then aged at constant temperature overnight (12 h) at 5˚C. The freezing was carried out in a batch soft ice cream maker. Apparent viscosity of ice cream mixes were evaluated using a rotational viscometer at 5˚C and 51.8 s-1. Before melting rate determination, samples were tempered at –18°C overnight, Ice cream samples (30 g) were put on a wire screen mesh and allowed to melt at ambient temperature. Melting rates were measured from the slop of linear portion of drained mass vs.time graphs. The pH values for mix samples were measured with a pH meter. After the mix was frozen in a batch freezer, Draw temperature of ice creams was obtained using a digital thermometer.Mix and ice cream samples (3 g) were diluted 1: 500 in two steps with deionized water and absorbance was measured by a spectrophotometer at 540 nm. Turbidity (%) was calculated as (absorbance in mix - absorbance in ice cream)/absorbance in mix 100%. A known volume of ice cream and mix were weight and overrun was determined as (weight of the mix - weight of the ice cream)/ weight of the mix 100%. Results & discussion: Reducing fat in any food formulation will cause a decrease in viscosity (Cody et al., 2007). Fat reduction decreased apparent viscosity (P0.05), ranging from 6.31 to 6.34. Draw temperature as a measure of freezing point of ice cream is dependent on the type and concentration of the soluble constituents and varies with the composition. Addition of some ingredients such as sweeteners, lactose and salts decrease the freezing point. Fat is immiscible with the aqueous phase and carbohydrate polymers are very large molecules, depression of the freezing point is caused indirectly by using of these materials, as a result of decreasing the water content (Marshall and Arbuckle, 1996). In this study, a reduction of fat content of full fat ice cream resulted in higher draw temperature. However, there was not a specific trend in the temperature values of samples with same fat content and different fat replacer levels. There was no significant difference between turbidity of samples with same kind of gum. Similar results were obtained by Schmidt et al. (1993), which related to sufficient amount of milk fat (2.1 and 4.8 %), milk proteins and emulsifiers in ice cream formulations. Conclution: Decreasing the fat content generally caused an increase in the value of overrun. But, very high viscosity of mix may prevent vigorous agitation and air incorporation that seems the reason of why increasing fat replacer concentration resulted in overrun reduction
