Effect Of Solar Drying Research Articles

Effect of Varieties, Solar Drying and Zeer Pot Refrigeration Lining Media on Physico – Chemical Characteristics of Chili Pepper Fruits

Chili peppers are used as food and contain food nutrients such as vitamins A and C, fibre, folic acid and potassium for proper human growth and development. In addition, they are used by industries for manufacturing alcoholic, culinary and pharmaceutical products however they are perishable and undergo physico - chemical changes to cause postharvest loss of chili peppers. Therefore, the main objective of the study was to investigate the effect of varieties, solar drying and zeer pot refrigeration lining media on physico – chemical characteristics of chili peppers. A 2 x 3 x 3 factorial experimental design in Randomized Complete Block Design (RCBD) was used to collect data for laboratory analyses. The study found – out that, varieties of chili peppers had significant effect (p < 0.05) on physico – chemical characteristics of chili peppers with red cayenne significantly recorded the best pericarp thickness (0.21mm), porosity (72.3%) total soluble solids (2.42%) and pH (5.38) but titratable acidity (0.56%) of chili pepper fruits was significantly (p < 0.05) higher in scotch bonnet. Also, on effect of solar drying on physico – chemical characteristics of chili pepper fruits, there were significantly (p < 0.05) better thickness of pericarp (0.23mm), total soluble solids (2.47%), titratable acidity (0.62%) and pH (4.64) shown in unblanched solar dried chili pepper fruits while the best porosity (71.19%) was noted in controlled chili pepper fruits. Again, on effect of lining media of zeer pot refrigeration on physico – chemical characteristics of chili pepper fruits, thickness of pericarp (0.22mm) was significantly (p < 0.05) higher in wood shavings used as zeer pot refrigeration lining media but total soluble solids (2.03%) and porosity (69.27%) were best indicated in styrofoam used as zeer pot refrigeration lining media. Titratable acidity (0.54%) and pH (5.00) were better shown in sand used as lining media of zeer pot refrigeration.

Assessment of the Quality Characteristics of Stropharia rugosoannulata Subjected to Five Different Drying Methods

The effect of solar drying (SD), room-temperature shaded drying (RSD), hot-air drying (HD), vacuum freeze drying (VFD), and microwave drying (MD) was compared on the sensory quality, nutrient substances, bioactive constituents, and antioxidant activities of dried Stropharia rugosoannulata. The results revealed that, in comparison with SD, RSD, HD, and MD, VFD mushrooms exhibited a better appearance with less shrinkage and an ideal colour with lower a colour difference. Meanwhile, a significantly higher content ( p < 0.05 ) of protein, carbohydrate, total sugar, and vitamin C was retained in VFD samples. The HD and VFD samples both had abundant total free amino acids and best met the ideal protein standard. Furthermore, VFD had advantages in terms of better preserving bioactive constituents and stronger antioxidant activities compared to other treatments. Therefore, the VFD-dried S. rugosoannulata obtained a better overall quality compared to the other four drying methods.

Effect of Solar Drying and Vinegar Pretreatment on the Antioxidant Properties and Bioactive Compounds of Sliced Ginger

A comparison of concrete solar dryer (CSD) to stainless steel solar dryer (SSSD) in terms of the effect of drying and 10% vinegar pretreatment on antioxidant activities of ginger rhizome using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity method, Ferric Reducing Antioxidant Power (FRAP) Assay, and total antioxidant methods was investigated. The effect of the two solar dryers and open-sun drying (OSD) on bioactive compound composition of the 10% vinegar pretreated sliced ginger using ethanol and aqueous extracts with GCMS/MS identification was also evaluated. The antioxidant activities of ethanol and aqueous extract of the 10% vinegar pretreated ginger using FRAP, DPPH, and total antioxidant methods were all higher than that of the dried samples, with CSD having the highest antioxidant activities among the dried methods. Drying reduced the main bioactive compound, which is gingerol, from 47.97% in the fresh sample to 32.49% in the OSD sample. The CSD sample demonstrated close likeness to the fresh sample with regard to retaining the highest gingerol and α-zingiberene. Hence, CSD can be adopted for commercial processing of ginger to reduce postharvest losses of the crop.

Energy and exergy analyses of solar drying sardine fillets

Fish is a highly perishable food product. It has a very short because it contains up to 78% of water. The aim of this work is to examine the effect of solar drying on the dehydration kinetics of Moroccan sardine fillets. The curves of the experimental kinetics of drying sardine fillets are carried out at four temperatures (50, 60, 70 and 80°C) with two air flow rates of 300 and 150 m3/h. Nine thin-film drying models are adapted to the drying data. The Midilli-Kucuk model allows better adaptation than the other models according to R2, S and χ2. The data shows that the moisture content reduced from 3.98% to 0.08% db (dry basis). In regards to a conducted study of a part concerning the exergy loss, exergy transfer rate from evaporation and exergy efficiency of the drying chamber is carried out.

Effect of Processing Methods on the Proximate Composition, Total Phenols and Antioxidant Properties of Two Mushroom Varieties

Mushrooms are traditionally consumed as food and are known to possess nutritional and medicinal properties. However, the choice of processing methods for mushrooms are often based on preference rather than the impact on nutritional or health benefits. The effect of solar drying, steaming and roasting on the proximate, phytochemicals and antioxidant activity of two mushroom varieties (Termitomyces schimperi and Volvariella volvacea) were investigated. Proximate analysis and phytochemical screening were carried out using standard protocols. The total phenols content and antioxidant activity were determined by means of Folin-Ciocalteu method and 1, 1-Diphenyl-2-picryl-hydrazyl (DPPH) assay, respectively. Results indicate that both processing methods and varietal differences had effects on nutrient composition of mushrooms. Solar drying retained most nutrients in both varieties. Dried T. schimperi had the highest protein content of 29.09 % whereas dried V. volvacea had the highest carbohydrate and ash contents of 60.71% and 5.56 %, respectively. Steamed mushrooms retained moisture and had the lowest carbohydrate content with steamed V. volvacea having the highest moisture and lowest carbohydrate values of 91.15% and 54.71%, respectively. Roasting also showed a high protein content of 28.65% in T. schimperi and a high carbohydrate of 58.65% in V. volvacea. None of the processing methods however had a significant effect on fat and fibre contents of both varieties used. The phytochemicals tested were present in both varieties in the processed and unprocessed forms. The steamed extract was the strongest scavenger of DPPH with 50 % inhibitory concentration (IC50) value of 3.03 ± 0.40 mg/mL whereas the unprocessed extract had the least effect with IC50 value of 9.35 ± 0.42 mg/ml. Similarly, the steamed extract recorded the highest total phenol content with value of 1644 ± 39 mg GAE/100 g whereas the unprocessed extract was the lowest with value of 1336 ± 93 mg GAE/100 g respectively. The present findings suggest that steamed mushrooms possess the highest antioxidant activity.

Effects of solar drying along with air recycling system on physicochemical and sensory properties of dehydrated pistachio nuts

Fresh pistachio was dehydrated with shade drying, sun drying, solar drying (without and with air recycling) systems (Methods I, II, III and IV). Then their impacts were studied on drying time, physical properties and also organoleptic criterions (shell appearance, color, roasted flavor, finger releasing kernel, sweetness, shell splitting and overall palatability) of dehydrated pistachio. The ambient-air temperature rise and drying time of pistachio in Methods I, II, III and IV reached to 1, 1, 14, & 17 °C; and 48, 19, 16, & 13 h, respectively. While the trends of drying rates in all methods were completely quadratic (R2 = 0.99), Method IV had the lowest shrinkage and the highest drying rate, shell splitting (70% more than Method I), bulk density and kernel density in comparison with other Methods. Whereas the pistachio's color properties (a, b and L), changed significantly when dried with Methods of I, II and III, the “L”, and “a” values of pistachio dried with Method IV had no significant difference with those dried with Method I (having the best color properties). The pistachio dried with Method IV (had the best sweetness and roasting flavor) in comparison with those dried with other methods because of higher drying rate.

Effect of Solar Drying on Physico-chemical and Antioxidant Properties of Mango, Banana and Papaya

Fruits play an important role in human nutrition, but due to their high perishable nature they cannot be stored for longer period. As drying is the ancient method of preservation, therefore, solar tunnel drying is done to evaluate the effect of drying on physico-chemical and antioxidant activity of mango, banana and papaya fruits. Fruits viz. mango and papaya were cut into slices while banana were made into rings (thickness of 1 ± 0.1 cm) and kept at a temperature of 60 ± 2 °C for 6 h under solar tunnel drier. During drying the removal of moisture content increased the physico-chemical properties viz. total soluble solids, acidity, reducing and total sugars of all the fruits. The antioxidant compounds, total phenols and total carotenoids were increased while heat sensitive vit-C decreased. However, the antioxidant activity, after drying, was increased in mango from 68.6 to 86.3 %, in papaya from 64.1 to 80.4 % and in banana from 59.5 to 73.2 %, respectively. Thus, solar tunnel drying is an inexpensive method of preserving the fruits efficiently and effectively for longer period of time.

CONVECTIVE SOLAR DRYING OF OLIVE LEAVES

ABSTRACT This paper presents investigations on thin layer convective solar drying of four olive leaves varieties (Chemlali, Chemchali, Chetoui and Zarrazi). Olive leaves were dried at three drying air temperatures (40, 50 and 60C) and at two drying air velocities (0.566 and 1.133 m/s). The drying air temperature is the main factor in controlling the drying rate. The experimental drying curves show the presence of only a falling rate period. Mathematical models, namely, Newton, Page, Henderson and Pabis, Logarithmic, Wang and Singh, Two‐term and Two‐term exponential models were fitted to the experimental data. Among these models, the Logarithmic model showed the best agreement with the experimental data. The effective moisture diffusivity was estimated by applying the Fickian law to the drying kinetics. The effective moisture diffusivity values varied from 3.437 10 −10 (Chemlali variety) to 2.427 10 −9 m2/s (Chemchali variety). The values of activation energy were calculated assuming an Arrhenius‐type temperature reliance. The activation energy ranged from 24.704 (Chetoui variety) to 53.743 (Chemlali variety) kJ/mol. The quality attributes of the dehydrated olive leaves samples were investigated in term of color. The effect of solar drying on L*, a*and b*parameters was significant (P < 0.05) for all the studied olive leaves.PRACTICAL APPLICATIONSThis work concerns the investigation of the drying characteristics of olive leaves. Like many other medicinal plants, olive leaves should be dehydrated before use to preserve their active compounds which have numerous applications in the pharmaceutical, cosmetic and food preservation industries. Therefore, the study of the drying characteristics is essential for the industrial and the academic purposes.

Effects of Drying on the Qualities of Some Selected Vegetables

The effect of solar drying on the quality of three species of vegetables is presented. These species are amaranthus (tete in local language), vernonia (ewuro) and fluted pumpkin (ugu). Proximate analysis and microbial load analysis were carried out on the vegetable samples after each day of drying for a total of 5 days. The solar irradiation for the period varied from 89 W/m2 to 203 W/m2. Both analyses show that the nutritional composition of the fresh vegetable and their microbial load decreases with each day of drying. To have maximal nutritional values from vegetables, it is best to consume them fresh. However, for storage purposes, two days of drying is sufficient to prevent spoilage and at the same time retain an average 70% of fat, 80% ash, 70% carbohydrate, and 60% protein of their initial nutritional composition.

Effect of solar drying on vitamin D3 and provitamin D3 contents in fish meat

La vitamine D3 (chlolecalciferol) apparait instable a la lumiere solaire, contrairement a la provitamine D3 (dehydro-7-cholesterol). Ceci suggere que la vitamine D3 dans le poisson n'est pas formee sous l'influence de l'exposition au soleil

The effect of solar drying and heating on the hardness of Phaseolus beans during storage

Small white beans ( Phaseolus vulgaris) were dried and heat processed before storage. Water removal in a solar drier was four times faster than conventional field drying in the pods. Heat treatments included particle-to-particle roasting using hot sand, and microwave heating. All samples stored for 212 days at low moisture contents (4–5%) showed a slow rate of hardening at a low temperature of 18°C and a high temperature of 34°C. However, heat treated and control beans became much harder when stored at a humidity of 9% and a temperature of 34°C. Heating and solar drying are effective treatments prior to bean storage, as they greatly reduce moisture to safer levels.