PEKMEZ-DAIRY DESSERTS FORTIFIED WITH SPRAY-DRIED DAIRY POWDERS: EFFECTS OF THE INTERACTION BETWEEN SKIM MILK POWDER, YOGHURT POWDER AND BUTTERMILK POWDER BY A MIXTURE DESIGN APPROACH

A mixture design approach was used to evaluate the interactions between skim milk powder (SMP), yoghurt powder (YP) and buttermilk powder (BMP) on rheological and sensory properties of dairy dessert mixture samples (DDMS). DDMS was prepared with pekmez powder, which was obtained by spray drying of pekmez, also known as concentrated grape molasses. Among the dairy powders, YP was the component that had the most effect on the viscosity of DDMS. The liking of the panelists was more prominent for the dairy dessert samples including the higher concentrations of YP. Optimum values of SMP, YP and BMP in the mixture were found to be 12–46%, 41–90% and 0–39%, respectively with respect to sensory properties.

PRACTICAL APPLICATIONS

The compositional properties of dairy powders can be changed by their usage at particular combinations, which could give rise to an improvement in their rheological and sensory properties. Such modifications would be of great economical importance to food industry. Dairy powders can be used to improve these properties when optimum combination levels of these dairy powders are taken into consideration. Therefore, information obtained in this study may be useful in practical industrial food product process monitoring and development.     

The effects of carbon dioxide addition to cheese milk on the microbiological properties of Turkish White brined cheese

This study invest0igated the effect of CO₂ added to achieve three pH levels: pH 6.1, pH 6.2 and pH 6.3 for treatments X, Y, Z, respectively, on some microbiological properties of Turkish White (TW) brined cheese. For each pH, four batches of cheese were produced from: raw milk with no added carbon dioxide (UR), raw milk with carbon dioxide (TR), pasteurised milk with no carbon dioxide addition (UP) and pasteurised milk with carbon dioxide addition (TP). The microbiological analysis of TW brined cheeses was carried out for 90 days of maturation period. Total aerobic mesophilic bacteria, mesophilic lactic acid bacteria, yeasts and moulds and coliform group were determined in control and CO₂ treatment groups. Mesophilic bacteria count was determined as 5.14, 5.29, 5.67 log cfu/g for pH 6.1, 6.2 and 6.3, respectively, in CO₂‐treated raw milk cheeses. Yeasts and moulds reduction increased significantly by applying CO₂ (P < 0.01). For TW cheese samples, the most significant microbial inactivation was detected at sample groups of pH 6.1.     

Assessment of glass fiber-reinforced polyester pipe powder in soil improvement

This study investigates the use of glass fiber-reinforced polyester (GRP) pipe powder (PP) for improving the bearing capacity of sandy soils. After a series of direct share tests, the optimum PP addition for improving the bearing capacity of soils was found to be 12%. Then, using the optimum PP addition, the bearing capacity of the soil was estimated through a series of loading tests on a shallow foundation model placed in a test box. The bearing capacity of sandy soil was improved by up to 30.7%. The ratio of the depth of the PP-reinforced soil to the diameter of the foundation model (H/D) of 1.25 could sufficiently strengthen sandy soil when the optimum PP ratio was used. Microstructural analyses showed that the increase in the bearing capacity can be attributed to the chopped fibers in the PP and their multiaxial distribution in the soil. Besides improving the engineering properties of soils, using PP as an additive in soils would reduce the accumulation of the industrial waste, thus providing a twofold benefit.     

The effects of starter culture on chemical composition, microbiological and sensory characteristics of Turkish Kaşar Cheese during ripening

Kaşar cheese samples were produced from raw milk and starter culture-added pasteurized milk. Chemical, microbiological and organoleptic properties of kaşar cheeses were analysed at certain times during the ripening periods (on the 1st, 7th, 15th, 30th, 60th, 90th days). Generally, chemical parameters were not affected by starter culture. The pH, ripening index, water-soluble nitrogen and non-protein nitrogen did not show significant differences between the cheese samples. The addition of starter affected the microbiological quality of the cheeses. Starter culture-added kaşar cheeses contained low levels of total aerobic mesophilic bacteria, moulds and yeasts, and coliforms, and achieved higher organoleptic scores than those of cheeses made from raw milk. The starter cultures contributed to acidity and microbial quality of the cheese.     

Shelf life determination of Yayik butter fortified with spice extracts

Sage ( Salvia officinalis L.), cinnamon ( Cinnamomum zeylanicum ), rosemary ( Rosmarinus officinalis L.), clove ( Syzygium aromaticum L.), sumac ( Rhus coriaria L.), oregano ( Origanum vulgare L.), ginger ( Zingiber officinale ), caraway ( Cuminum cyminum L.) and thyme ( Thymus vulgaris L.) extracts were added at two concentrations (0.2 and 0.5%) to yayik butter. The butter samples were stored at two different temperatures, 4°C and 25°C. Product acceptability was monitored following the Weibull Hazard sensory method where the end of shelf life was the time at which 50% of panellists found the product unacceptable. Ginger, thyme and cinnamon extracts increased the shelf life of yayik butter and were comparable to the synthetic preservatives sorbic acid and BHA. The shelf life of the samples stored in the refrigerator was approximately twice as long as the samples stored at room temperature.     

Effects of sunflower honey on the physicochemical,microbiological and sensory characteristics in set type yoghurt during refrigerated storage

The primary purpose of this research was to monitor the influence of sunflower honey addition (2%, 4% and 6% w/v) to yoghurt milk on survival of the microbial flora of yoghurt and the physicochemical and sensory characteristics during refrigerated storage for 4 weeks. The water activity decreased according to the addition of honey with higher concentrations in the storage period (4°C). At the end of fermentation, pH values of yoghurt samples ranged between 4.33 (without honey) and 4.52 (addition of honey with 6%). The highest water holding capacity, consistency and the lowest brightness values were determined in the groups produced with 6% honey addition. The water holding capacity and a* (redness) values of the honey incorporated yoghurt samples increased during storage. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus values of the yoghurt with honey increased compared with the control group samples (P < 0.01). Addition of honey to yoghurt milk has affected the vitality of the characteristics starters in the incubation and storage time of the yoghurt samples (P < 0.01). Optimum sweetness was obtained with the samples containing 4% honey level.