Refractance window drying in the production of instant baker's yeast and its effect on the quality characteristics of bread.

The study aimed to produce instant dried baker's yeast (BY) by conventional or infrared-assisted refractance window drying (RWD or InfraRWD, respectively) and compare their bakery performance with commercial BY. According to the findings of the study, the total yeast count was higher than 9.60 log cfu/g in all dried BY samples, and the lowest viability was obtained in BY dried by InfraRWD at 50°C. In general, BY produced by RWD increased the physical quality parameters of bread such as specific volume, total cell count, and the number of cell areas of bread crumbs. Moreover, bread leavened by BY dried by RWD slowed down the staling rate of bread, while infrared assistance accelerated the staling. Sensorial analysis showed that bread produced by refractance window dried BY was more acceptable than commercial BY. In a conclusion, RWD can be an effective alternative to the production of instant baker's yeast, but the most quality features of BY has negatively affected by infrared assistance. PRACTICAL APPLICATION: In the drying of baker's yeast, promising advantages can be obtained by refractance window drying. The higher specific volume and superior bread crumb with a retarded staling rate were determined when bread was produced by the refractance window. This is the first time that RWD and InfraRWD have been used for the production of instant baker's yeast and it has several practical applications for bread quality.

Usability of soapwort and horse chestnut saponin extracts as foaming agents in foam mat drying of pomegranate juice.

BACKGROUND: This study evaluated the usability of saponin-rich extracts (soapwort and horse chestnut) as a foaming agent for foam mat drying of pomegranate juice. RESULTS: According to the foaming and stabilization studies, the optimum conditions were determined as 0.4% of soapwort extract, 0.03% of carboxymethyl cellulose as a stabilizer, and 3 min of whipping time. The foams produced using these conditions were dried at different spreading thicknesses and drying temperatures. The results showed that the thicker spreading thicknesses provided a higher antioxidant activity. On the other hand, drying temperature had a significant effect on all measured parameters except moisture content and water activity. The higher drying temperature caused a greater colour change and a lower content of total phenolics, total monomeric anthocyanins, cyanidin-3-glucoside, and delphinidin-3-glucoside. On the other hand, a higher content of ascorbic acid and better antioxidant activity was determined in the samples dried at 70 °C. CONCLUSION: According to the results obtained, spreading thickness of 2 mm and drying temperature of 70 °C were suggested for pomegranate juice powder production by foam mat drying. Overall, it was demonstrated that saponin-rich extracts are a good foaming agent alternative that provides foaming at very low concentrations and a product with high quality. © 2020 Society of Chemical Industry.

Growth, water use, yield and quality parameters in oregano affected by reduced irrigation regimes.

BACKGROUND: Determining plant tolerance to water stress is necessary in irrigation scheduling, decisions concerning supplementary irrigation, planning and operation and, more importantly, the rational use of water resources. In the present study, effects of the irrigation regime on oregano growth, water use, yield and quality parameters were investigated using reduced irrigation regime treatments. RESULTS: Increased water stresses caused a decrease in all growth and yield parameters. Plant water use efficiency was not significantly different among the control, low and medium stress treatments, although it was the lowest for the extreme water stress treatment. Total essential oil yield was the only quality parameter demonstrating significant differences among treatments. Yield response factors were determined as 1.13, 1.12, 1.06 and 1.10 for total fresh, total dry, dry leaf and total essential oil yields, respectively. CONCLUSION: Yield response factors indicate that oregano plant is slightly sensitive to water stress. Although the yield parameters were affected by water stress, Origanum onites, under cultivation in recent years, might have developed a resistance mechanism for quality parameters because it has grown in very dry conditions under a natural environment for many years. However, the negative relationships between crop evapotranspiration versus essential oil, total phenolic and flavonoid contents and extract yield indicates that the quality parameters of oregano under low plant water consumption may be increased. © 2020 Society of Chemical Industry.

Influence of microwave, the combined microwave/hot air and only hot air roasting on the formation of heat-induced contaminants of carob powders.

This study aims to investigate the effects of microwave, combined microwave/hot air treatment and hot air-only roasting on the formation of heat-induced contaminants of carob powders. Moisture content, water activity and pH values of the product decreased with the increasing roasting time and microwave power, while browning index (BI) and ultraviolet absorbance (UV-A) values were increased. While L and b values of carob powders decreased with increasing the roasting time and microwave power, a and ΔE values were increased. Varying roasting conditions also significantly affected the content of Maillard reaction products (MRPs): 5-hydroxymethylfurfural (HMF) (0.69-28.32 mg/kg dry matter), furfural (

Functional properties of chickpea protein isolates dried by refractance window drying.

In the present study, the effect of Refractance Window (RW) drying on the functional properties of chickpea protein isolates was investigated and compared to freeze drying at different pH levels. The functional properties investigated were protein solubility, water and oil holding capacity, emulsifying properties, foaming properties, flocculation and coalescence indices and textural properties. The solubility, oil holding capacity and foam stability of the freeze dried protein isolates were determined to be higher than the RW dried samples. On the other hand, the RW dried samples had better water holding capacity and emulsion stability compared to the freeze dried protein isolates. The emulsion activity index, flocculation and coalescence indices of the chickpea protein isolates prepared by different drying techniques showed different tendencies depending on the pH level. Freeze dried protein isolates exhibited higher gelation ability than RW dried samples according to the texture profile analysis. This study clearly showed that the drying technique used in the preparation of protein isolates can affect their functional properties.

Effect of vegetable proteins on physical characteristics of spray-dried tomato powders.

In the present study, the effectiveness of different vegetable proteins (pea protein isolate, soy protein isolate and zein from maize) at two different ratios (1% and 5%) on product yield and physical properties of spray-dried pulpy tomato juice was investigated. Additionally, these proteins were compared with whey protein concentrate which has a superior effect on spray dried products at the same concentrations. Additionally, plain tomato juice was also spray dried for comparison with vegetable proteins. The product yield of the tomato powders dried with the vegetable proteins was lower than with the whey protein concentrate. Among vegetable proteins, the highest product yield was produced with 1% soy protein isolate. In all products, there was a slight colour difference between the reconstituted tomato powders and the raw tomato juice, which indicated that pulpy tomato juice can be spray dried with minor colour change. All powders had unique free-flowing properties estimated as Carr index and Hausner ratio due to their large particles.