THIN-LAYER INFRARED RADIATION DRYING OF RED PEPPER SLICES

Drying characteristics and changing of quality parameters of red pepper were determined experimentally as a function of infrared power ( IP ) and air velocity during infrared drying. Drying experiments of red pepper slices were carried out at three levels of IP (300, 400 and 500 W) and at three air velocities (1.0, 1.5 and 2.0 m/s). The drying time at air velocity from 1.0 to 2.0 m/s ranged between 314 and 455 min, 213 and 297 min and 196 and 230 min at IP of 300, 400 and 500 W, respectively. Drying rate increased with increasing IP and decreasing air velocity. All drying experiments had a falling rate of drying period. The specific energy consumption was varied between 4.62 and 7.59 kW·h/kg for all the drying conditions. Thickness change/shrinkage was found to be in the range of 0.162 and 0.263. The color parameters and the rehydration ratio were significantly influenced by IP and air velocity.

PRACTICAL APPLICATIONS

Drying is an important operation in red pepper processing. In open-air condition, the drying time of red pepper is 8–10 days. Several researchers state that drying in open-air conditions also has some disadvantages such as lack of ability to control the drying operation properly, long drying time, weather uncertainties, high labor costs, large area requirement, insect infestation and contamination with dust and other foreign materials. The results from this study can be used as reference for drying of red pepper in similar applications. The drying method proposed in this study decreased the time required for drying of red pepper, reduced the space needed for equipment and protected the product quality. Therefore, the drying technique proposed in this study can be a good alternative to other drying techniques available. Also, the proposed drying method can be used as a reference to drying applications of various vegetables and fruits.     

EFFECT OF THE USE OF DIFFERENT LACTIC STARTERS ON THE MICROBIOLOGICAL AND PHYSICOCHEMICAL CHARACTERISTICS OF NATURALLY BLACK TABLE OLIVES OF GEMLIK CULTIVAR

The effect of different lactic acid bacteria cultures on the physicochemical and microbiological characteristics of brined black olives of Gemlik cultivar at low fermentation temperature was studied. Fermentation was carried out according to the traditional Gemlik method with modifications like low salt concentration and lactic starter addition. The brines with 7% salt concentration were inoculated with lactic acid bacteria ( Lactobacillus brevis, Leuconostoc cremoris and L. paramesenteroides ), which were previously isolated from olive fruits at low temperatures and a commercial strain of Lb. plantarum. Fermentation procedures were carried out at controlled temperatures (between 10–12C). Lactic acid bacteria survival was accompanied by yeast development, no Pseudomonas and Enterobacter species were detected in all treatments during fermentation. The highest total titratable acidity, lowest pH and least yeast growth were determined at the brines and fermentation products, which were inoculated with L. cremoris.

PRACTICAL APPLICATIONS

The use of suitable starter cultures is necessary to improve the microbiological control of the naturally black table olive process, help to standardize the fermentation, increase the lactic acid yield and accordingly provide the production of olives with high quality. The requirements mentioned for starter cultures include a rapid and predominant growth, homofermentative metabolism, tolerance to salt, acid and polyphenols, and few growth factor requirements. Especially at the regions where olives were picked later when environmental temperatures are lower, the use of a starter culture that has the ability to grow at low temperatures may be necessary. Use of such starter cultures may help to increase acidification, to control some types of spoilage and to shorten the fermentation process.     

Performance of an approximation to continuous review (s,S) policies under compound renewal demand†

Performance of an approximation to continuous review (s,S) inventory policies under constant lead time, full backlogging, compound renewal demand, and a linear cost structure is examined. The approximations are based on a lower bound for the optimal order-up-to level and the corresponding best reorder point. It is shown that the approximate policy is unique and that it performs better under relatively higher shortage costs, longer lead times, and lower set-up costs. Both exact and approximate policies are computed and the corresponding objective function values are compared under a large number of different parameter settings. The average relative approximation error is found to be 2·23% with a 27-fold average reduction in computing times.     

Effect of shooting period, region of growth and processing method on the Fe and Mn content of tea determined by X-ray fluorescence

X-ray fluorescence (XRF) is an effective technique for qualitative and quantitative analysis of minerals in various agricultural products. Simplicity, high throughput and the possibility of automation make it useful for screening large numbers of samples. Samples of 138 fresh green, black tea and residue of this black tea after brewing were obtained from the Eastern Black Sea region of Turkey and analysed for Fe and Mn content using XRF. Such work appears not to have been reported so far.     

Evaluation of neopterin levels in patients undergoing hemodialysis

Neopterin is a diagnostic or a prognostic biomarker for several pathologies including renal diseases. However, the association between neopterin status and causative main reasons such as diabetes and hypertension for renal disease remains unclear. The aim of the study was to evaluate neopterin levels in diabetes and hypertension patients treated with/without hemodialysis. According to primary renal disorders, the patients undergoing hemodialysis were classified into 4 groups as diabetic nephropathy, hypertensive nephropathy, reflux nephropathy or interstitial nephritis, and others. The controls consisted of healthy subjects, hypertensive subjects, and diabetic individuals without any renal disorder. In the study, both urinary and serum neopterin levels were measured using high performance liquid chromatography and enzyme‐linked immunosorbant assay in patients undergoing regular hemodialysis therapy (n=71). The effects of the duration of hemodialysis and treatment of erythropoietin and/or iron on neopterin levels were also evaluated. Neopterin levels were found to be higher in hemodialysis patients than in the healthy controls (P<0.05). A significant difference in neopterin levels was also found between diabetic control patients and diabetic nephropathy patients (P<0.05). A similar significant difference was detected in neopterin levels between hypertensive patients with/without nephropathy (P<0.05). Neopterin may be an early critical marker for progression of nephropathy in diabetic and hypertensive patients in early stages.