Physical properties of yoghurt powder produced by spray drying

WOS: 000338235300018PubMed ID: 24966433The study is an extension of an optimization study, which was planned to determine the optimum spray drying conditions (the feed, outlet and inlet air temperatures) for producing yoghurt powder. The resulting yoghurt powder at each condition was subjected to the measurement of physical properties, moisture content, and reconstitution properties. All the reconstitution properties of yoghurt powders produced under 20 different spray drying conditions according to CCRD experimental design were affected by the drying outlet temperature only. Furthermore, the bulk (bulk and tapped densities, porosity, flowability, hygroscopicity and degree of caking) and particle properties (particle size distribution, particle density and morphology) of yoghurt powder obtained from optimum spray drying conditions were also determined. The bulk, tapped and particle densities of yoghurt powder were 538, 746 and 1177 kg/m(3), respectively. The mean diameter (D-4.3) and the span value of yoghurt powder were 3.053 and 2.487 mu m, respectively.TUBITAK-TOVAGTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [107 O 090]; Ege University, Council of Scientific Research ProjectsEge University [BAP 2006/Muh/043]; Pinar Dairy Products Company, Izmir, TurkiyeThe authors acknowledge the financial support of TUBITAK-TOVAG (project number: 107 O 090) and Ege University, Council of Scientific Research Projects (Project Number: BAP 2006/Muh/043) and also Pinar Dairy Products Company, Izmir, Turkiye

Yoghurt with candied chestnut: freeze drying, physical, and rheological behaviour

WOS: 000345916400044PubMed ID: 25477665As a novel product, yoghurt powder was produced by freeze drying and with added candied chestnut puree at ratios of 5, 10, and 20 % by weight. During the freeze drying process, mass loss, water activity, and the moisture content of the samples were determined and the colour (Hunter L, a, b) of the yoghurt powder products was measured. Results showed that increasing the percentage of candied chestnut puree resulted in an increase in water activity, moisture content, and colour change values of the end product. The drying behaviour, drying rate versus free moisture content, was also investigated. It was observed that yoghurt with or without added candied chestnut puree could be satisfactorily freeze-dried. Moreover, the performance of the dried product was observed in a ready-to-use, reconstituted form. For this purpose, the obtained powders were reconstituted to their original moisture contents. Shear stress and apparent viscosity against shear rate in a range of 1-1,000 (1/sec) was then measured by a Haake-Mars rotary viscometer. According to the results, the apparent viscosities of reconstituted products, as plain yoghurt and the one with an added 5 % chestnut puree were lower than that of fresh yoghurt. However, reconstituted yoghurts containing 10 % and 20 % chestnut puree had apparent viscosities higher than fresh yoghurt. Power Law explained well the rheological behaviour of reconstituted yoghurt samples for the applied shear rate range. Based on rheological data and sensory analysis, it was concluded that the freeze dried yoghurt containing 10 % (w/w) candied chestnut puree was an acceptable novel product

Kinetics of colour, chlorophyll, and ascorbic acid content in spinach baked in different types of oven

WOS: 000411513500004Spinach was baked in steam-assisted hybrid ovens, natural and forced convection ovens, and saturated steam ovens at different temperatures and baking times. The moisture content, water activity, peroxidise activity, colour, ascorbic acid, and chlorophyll content were determined for each baking time and kinetic analysis of thermal degradation of the colour, chlorophyll, and ascorbic acid were evaluated. Degradation of green colour, total chlorophyll, and ascorbic acid in spinach leaves during the baking process was considered as first order reaction kinetics and temperature dependency of degradation was described by the Arrhenius equation. Baking in steam-assisted hybrid ovens resulted in the highest rate of reaction for both colour change and chlorophyll degradation, followed by forced convection and then natural convection ovens. The existence of steam in the baking chamber resulted in an acceleration of the baking process and better ascorbic acid retention in spinach was determined by baking in steam-assisted hybrid ovens. Degradation kinetics could allow definition of optimum baking temperatures and times in different types of ovens and shorter baking times should be preferred in steam-assisted hybrid ovens if fresh appearance (high greenness) is desired.Scientific and Technical Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TOVAG 109 O 087]This research was supported by the Scientific and Technical Research Council of Turkey (Project No. TOVAG 109 O 087)

Improving Functionality of Whole Egg Powder by the Addition of Gelatine, Lactose, and Pullulan

WOS: 000297457000016PubMed ID: 22416722The addition of gelatine (G), lactose (L), pullulan (P), and their mixtures at equal ratios (gelatine + lactose [GL] and gelatin + pullulan [GP]) to whole egg prior to drying was studied. Their effects on the functional properties (emulsion and gelling ability, water holding capacity of gel, foaming, color) and soluble protein content of spray dried egg powder during the 6 mo of storage at 20 degrees C and 50% relative humidity were investigated. It was demonstrated that the emulsion and foaming stability, water holding capacity of gel, and color change were significantly affected by the storage time, whereas storage time did not affect the strength of gel texture prepared by egg powders. Gelatine and pullulan improved the foaming stability and water holding capacity. Lactose caused a decrease in emulsion and foaming stability values. The maximum color change was observed for the plain egg powder, showing that mixing whole egg with carbohydrate- and/or protein-based additives before the drying process preserved the color of egg powder. Adding carbohydrate and/or protein caused significant changes in functional properties of egg powder.TUBITAK-TOVAGTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [108 O 541]; Ege Univ., Council of Scientific ResearchEge University [BAP 2008/MUH/012]; Ege Univ., Science and Technology CenterEge University [EBILTEM 09/BIL/014]The authors acknowledge TUBITAK-TOVAG (Project nr 108 O 541), Ege Univ., Council of Scientific Research Projects (Project nr BAP 2008/MUH/012), and Ege Univ., Science and Technology Center (Project nr EBILTEM 09/BIL/014) for financial support. The authors also thank Mix Food Company, Izmir, Turkey, for material support

Physicochemical Characterization of Whole Egg Powder Microencapsulated by Spray Drying

WOS: 000290872900006Physical characterization and oxidative stability of egg powder microencapsulated by spray drying were studied in this work. The wall material (gelatin, lactose, pullulan, and their mixtures) and liquid egg mixtures were prepared by homogenization at 22,000 rpm for 60s. The spray drying was carried out at pilot-scale spray dryer (Niro Mobile Minor, Soborg, Denmark). The spray-dried egg powders were analyzed for moisture content, water activity, peroxide value, total cholesterol oxidation products (TCOPs), particle properties, and bulk properties. Using gelatin as wall material resulted in a significant increase in the moisture content and water activity of egg powder during storage and it improved flowability. Egg powders containing pullulan as wall material showed a fibrous structure and had the lowest bulk density. Adding lactose as wall material increased the oxidative stability, which was indicated with lowest peroxide value and TCOPs level of egg powder.TUBITAK-TOVAGTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [108 O 541]; Ege University, Council of Scientific Research ProjectsEge University [BAP 2008/MUH/012]; Ege University, Science and Technology CenterEge University [EBILTEM 09/BIL/014]The authors acknowledge TUBITAK-TOVAG (Project Number: 108 O 541); Ege University, Council of Scientific Research Projects (Project Number: BAP 2008/MUH/012); and Ege University, Science and Technology Center (Project Number: EBILTEM 09/BIL/014) for financial support. The authors also thank Mix Food Company, Izmir, Turkey, for material support

FREEZE DRYING OF YOGHURT WITH CANDIED CHESTNUT PUREE: SURVIVAL OF LACTIC ACID BACTERIA AND DETERMINATION OF PHYSICAL PROPERTIES

WOS: 000329468500014Yoghurts with varying candied chestnut puree contents were freeze dried to produce a novel product: yoghurt powder containing candied chestnut puree. The amount of surviving lactic acid bacteria in the products was determined. The results showed that increasing the percentage of candied chestnut puree resulted in a decrease of moisture content, water activity, ash content, and L*values of the powder. Yoghurt with candied chestnut puree could be satisfactorily freeze dried with a minimum level of 8.93 log cfu/g dry matter survival rates for the lactic acid bacteria