Effects of different drying methods and packaging materials on the physical and sensory qualities of tomato (Lycopersicon lycopersicum L.)

Fresh tomato fruits have a very limited shelf life partly due to their high moisture content and respiration rate. A possible way of storing tomato fruits is to dry and process them into powder or paste. Therefore, this research was conducted to determine the effects of drying methods and packaging materials on physical and sensory qualities of powdered tomato in Yola, Adamawa State, Nigeria. Harvested fruits of tomato variety, “Rio de grande” were subjected to blanching and subsequent drying methods and packaging materials. The experiment was laid out in a Completely Randomized Design (CRD); with the drying methods placed in main plot while the packaging materials in sub-plot and repeated three times before storage for twelve weeks. At four weeks of storage, oven drying method was found to be statistically different (p≤0.05) in terms of water absorption capacity value of 3.19 (mg/100g). The glass jars performed better than polythene bags in color retention, taste and consistency at four weeks of storage. The study shows that tomato fruits can be successfully dried using oven, sun and shade drying methods but preferably oven drying method. The processed powder could be successfully stored for 12 weeks or above using either glass jars or plastic container without affecting the consumer appeal and this will also reduce the postharvest losses of tomato fruits.

Effect of Supplementation of Dried Bioflocs Produced by Freeze-Drying and Oven-Drying Methods on Water Quality, Growth Performance and Proximate Composition of Red Hybrid Tilapia

Supplementation of dried bioflocs for red hybrid tilapia (Oreochromis sp.) was examined during 57 days of feeding trials. Five experimental treatments; T1 (the control; without bioflocs), T2 (4% freeze-dried bioflocs), T3 (16% freeze-dried bioflocs), T4 (4% oven-dried bioflocs), and T5 (16% oven-dried bioflocs) were prepared to examine the water quality, growth performance and body composition of red hybrid tilapia. T2 and T4 treatments resulted in a higher growth rate and survival similar to the control, while T3 and T5 treatments showed the lowest values of growth performance among all treatments. T1 treatment showed the best quality of culture water followed by T2 and T4 treatments, while T3 treatment resulted in poor water quality followed by T5 treatment. Based on these results, the ratios of bioflocs (4% and 16%) had more effect on fish growth and water quality than the drying methods (freeze-drying and oven-drying). The ratio of 4% freeze-dried or oven-dried bioflocs provided higher growth rates and better water quality parameters similar to the control, while the ratio of 16% showed the worst growth performance and water quality in the present study. In addition, body compositions of tilapia fed 4% dried bioflocs showed better nutritional value than tilapia fed 16% dried bioflocs. Protein and energy levels showed an increasing trend with decreasing supplement levels of bioflocs. Moisture content was significantly higher when supplementation of 16% bioflocs was used. Overall, supplementation of 4% freeze-dried or oven-dried bioflocs can be successively included in red hybrid tilapia diets without any effects on growth or body composition and can result in a good quality of culture water for red hybrid tilapia.

Metoda Pengeringan Zat Warna Bubuk Ekstraksi Kulit Bawang Merah menggunakan Convection Oven-drying dan Spray-drying

Pigmen warna dalam kulit bawang merah hasil ekstraksi mengandung senyawa yang dapat memberi warna pada kain. Ekstrak dalam bentuk cair tidak tahan lama dalam penyimpanan sehingga dibuat dalam bentuk bubuk agar lebih tahan lama. Tujuan dalam penelitian ini adalah untuk mendapatkan zat warna lebih tahan lama dalam penyimpanan dengan cara pengeringan. Proses pengeringan zat warna yang dilakukan pada penelitian ini menggunakan oven dan spray dryer. Karakterisasi yang digunakan untuk mengevaluasi hasil pencelupan menggunakan spektrofotometri, Laundry-O- meter untuk ketahanan terhadap pencucian dan crockmeter untuk ketahanan terhadap gosokan. Hasil yang didapat dari penelitian ini adalah berat kering zat warna bubuk Hasil pengeringan menggunakan oven dan spray dryer masing-masing sebesar 4,97 gram dan 2,68 gram dari 1 Liter larutan ekstraksi. Kandungan air yang terdapat dalam zat warna bubuk dengan pengeringan menggunakan oven sebesar 35% sedangkan menggunakan spray dryer sebesar 3% setelah didiamkan selama 2 bulan. Evaluasi terhadap hasil pencelupan menggunakan zat warna bubuk hasil pengeringan menggunakan oven dan spray dryer masing-masing memiliki ketuaan warna (K/S) sebesar 3,46 ; kerataan warna (standar deviasi) sebesar 0,105; kecerahan dan arah warna L* 74, 28 ; a* 0,68 dan b* 25,55 ; dan ketuaan warna (K/S) sebesar 3,05 ; kerataan warna (standar deviasi) sebesar 0,08 ; kecerahan dan arah warna L* 77,19 ; a* - 2,03 dan b* 27,32. Untuk ketahanan luntur warna terhadap pencucian dan ketahanan warna terhadap gosokan basah serta kering keduanya memiliki hasil yang sama yaitu 4-5 dan 5. Kandungan air zat warna bubuk dan kerataan warna yang lebih baik dihasilkan dengan pengeringan menggunakan spray dryer.

The Effect of Drying Processes on the Nutritional and Phytochemical Levels of Chia Leaves (Salvia hispanica L.) at Different Stages of Growth

Chia leaf (Salvia hispanica L.) is an underutilized low-cost source of nutrients. The leaf is currently not widely utilized as compared to the chia seeds which have wide use in the food industry. The present study investigated the effect of solar-drying and oven-drying chia leaves harvested at different stages of growth on their nutritional and phytochemical composition. The chia leaves were harvested at four stages of early vegetative stage, late vegetative stage, budding stage and flowering stage. Oven drying was done at45 ºC for 24hours, and solar dried in a solar drier until a constant weight was achieved. The results indicated significant differences (p<0.05) between treatments and stages of maturity. Results also showed that solar dried had better nutritional and phytochemical retention over oven dried chia leaves. Crude protein was highest in solar dried leaves at early vegetative stage (FS1) 4.48%, compared to 4.44% for oven dried chia leaves. The fiber content increased from the fresh leaf at 12.4% to high content in solar dried leaf at the early vegetative stage at 23.33%, while oven dried leaves had high content at the flowering stage at 22.09%. There were minimal changes in fat content of the dried chia leaves compared to fresh sample at 5.908%, with high fat levels noted for oven dried leaf at the early vegetative stage (FS3) at 5.68% and solar dried leaves at 4.71% at the budding stage. The difference in fat content could be attributed to degradation during the drying processes. Ash content on the other hand showed difference at different stages of growth from raw samples for both solar- and oven dried leaves. Highest retention of phenolic content was recorded at 147.62 mg/GAE for solar dried leaves at the budding stage (FS3). However, oven dried leaf samples recorded high phenolic content at 124.06 mg/GAE at the late vegetative stage. The flavonoid levels were recorded highest for solar dried leaves at the budding stage at 299.8 mg/CE, compared to high content for oven dried leaves at the budding stage recorded at 270.4 mg/CE. Scavenging activity was highest recorded for solar dried samples at the budding and flowering stages at 100 µg/100g compared to oven dried leaves at 80.85 µg/100g at the late vegetative stage. Solar drying is the simplest and convenient low-cost technology for preserving the nutritional quality and retention of phytochemical ranges of chia leaves which will enhance their utilization when abundantly available.

Probiotic powder: Optimization of the process parameters and influence of the drying method

This research paper aimed to optimize the process parameters and to select the most suitable drying method in order to obtain probiotic powder at reduced cost. The influence of the addition of growth promoters (glucose, sucrose, cheese whey, peptone, yeast extract or ammonium sulfate), incubation parameters (time and temperature) and drying method (freeze-drying or oven-drying) on the viability of the probiotic cultures Lactobacillus casei or Lactobacillus acidophilus was evaluated. The effect of the growth promoters was evaluated using a fractional factorial experimental design 26-4 and the concentration of the growth promoters and the incubation temperature were optimized through Box-Behnken experimental matrix (33). Cheese whey (16% w/v) plus ammonium sulfate (2.5% w/v) and cheese whey (12% w/v) plus yeast extract (7% w/v) promoted a higher multiplication of L. casei and L. acidophilus, respectively. The best temperature for L. casei was 35 ºC and for L. acidophilus 39 ºC, without influence of the incubation time (24 or 48 h). The oven-drying resulted in the highest populations of the probiotic cultures (above 9 log cfu/mL). This study proved that cheese whey can be a suitable growth promoter for both probiotic cultures and oven-drying could be the drying method, which can decrease the production costs. The influence of the temperature and growth promoters is strain specific, demonstrating that the growth conditions should be evaluated for each probiotic strain.

Experimental Investigation on the Influence of Oven-Drying on the Geotechnical Properties of Volcanic Ash-Derived Residual Soils

For thousands of years, the volcanic activity present along the Andes Mountain range has generated a large amount of pyroclastic material. As a result, around 60 percent of the soils present in Chile have a volcanic origin, of which, we can find soils derived from volcanic ash. These correspond to soils whose origin is the weathering of volcanic ash, which generates minerals such as allophane, imogolite, and halloysite. The presence of these minerals gives these soils unique geotechnical properties, such as high plasticity, low dry unit weight, and a unique internal structure. Subjecting these soils to extreme temperatures like those needed to perform standard laboratory tests produces changes in their structures, and thus in their geotechnical behavior. These changes are important to be aware of with respect to slope stability problems, embankment conformation, surface foundations, etc. In the present study, a type of soil found in Chile originating from the weathering of volcanic ash and locally named Trumao was studied. Due to its age and formation processes, the main minerals found in the soil are allophane and imogolite, and hence it belongs to the allophanic soil type. The material was studied in its natural state (undisturbed) and, after being oven-dried using common geotechnical tests, the behaviors of both samples were compared. The study shows that some properties are affected significantly by the oven-drying process, and thus it is not recommended to expose the material to high temperatures during geotechnical laboratory testing to avoid misleading results.

Effects of Ginger and Garlic on the Proximate and Mineral Compositions of Differently Processed Nile Tilapia (Oreochromis niloticus)

Freshly caught Nile Tilapia (Oreochromis niloticus) samples were obtained from Sabiyel Lake in Aliero Local Government Area of Kebbi State. Oreochromis niloticus samples were descaled, degutted, cut into chunks and rinsed with clean water at Fisheries Laboratory, Department of Forestry and Fisheries, Kebbi State University of Science and Technology, Aliero. The samples were subjected to different treatments designated as; T1 (oven drying), T2 (Frying), T3 (smoking), T4 (oven-dried + 5% ginger-garlic), T5 (Fried + 5% ginger-garlic), T6 (smoked + 5% ginger-garlic), T7 (oven-dried + 10% ginger-garlic), T8 (Fried + 10% ginger-garlic), T9 (smoked + 10% ginger-garlic), T10 (oven-dried + 15% ginger-garlic), T11 (Fried + 15% ginger-garlic), T12 (smoked + 15% ginger-garlic). The processed samples were taken to Agric. Chemical Laboratory, Faculty of Agriculture, Usmanu Danfodio University Sokoto, Nigeria, for the determination of proximate and mineral compositions. The treatments were analysed in 2 phases: at week 0 for the first phase of analysis and after 8 weeks of storage in an airtight plastic container at room temperature. The samples were then taken to the laboratory for the second phase of analysis. This study revealed that processing (oven drying, frying and smoking) of Oreochromis niloticus with ginger-garlic gave high nutritive content after 8 weeks of storage and thus might prevent the use of obnoxious substances as a means of preservation and substantially improve consumer’s satisfaction and quality fish protein intake.

A metabolomics approach to evaluate the effect of lyophilization versus oven drying on the chemical composition of plant extracts

Lyophilization is the “gold standard” for drying plant extracts, which is important in preserving their quality and extending their shelf-life. Compared to other methods of drying plant extracts, lyophilization is costlier due to equipment, material and operational expenses. An alternative method is post-extraction oven-drying, but the effects of this process on extract quality are unknown. In this study, crude extracts from Arthrocnemum macrostachyum shoots were compared using three post-extraction drying methods (lyophilization and oven drying at 40 and 60 °C) and two extraction solvents (water and aqueous 50% ethanol). Untargeted metabolomics coupled with chemometrics analysis revealed that post extraction oven-drying resulted in the loss of up to 27% of molecular features when compared to lyophilization in water extracts only. In contrast, only 3% of molecular features were lost in aqueous 50% ethanol extracts when subjected to oven drying. That is to say, ethanol used as a solvent has a stabilizing effect on metabolites and enhances their resistance to thermal transformation in the oven. Collectively, oven-drying of extracts was as effective as lyophilization in preserving metabolites in extracts only when 50% ethanol was used as a solvent. The results presented in this paper demonstrate the value of selecting solvent-appropriate post-extraction drying methods.

Influence of Drying Techniques on the Physicochemical, Nutritional, and Morphological Properties of Bighead Carp (Hypophthalmichthys nobilis) Fillets

Different experiment analyses were performed to evaluate the influence of two drying techniques (oven drying and microwave drying) on the fillets of bighead carp fish (Hypophthalmichthys nobilis). The processed and fresh samples were subjected to the chemical analysis of (amino acids, minerals, volatile compounds, fatty acids, and vitamins) as well as scanning electron microscopy, thermal analysis, and color measurement, in order to identify nutritional components that can be additives or supplementary in food industries. The drying techniques increased the protein content significantly. Amino acids were identified, and the level of essential amino acid (EAA) was higher under the microwave treatment compared with the oven drying process. The Ca+2 and K+1 were presented in high values, followed by Na+1 and Mg+2. In addition, the drying techniques showed and released more volatile compounds in the processed samples compared with the unprocessed samples. Under the drying process, polyunsaturated fatty acids were increased in the processed fillets, whereas the level of saturated and monounsaturated fatty acids reduced. Thermal degradation occurred from 100 to 150 °C. However, the processed samples were subjected to an intensive endothermic response, but remained stable until 100 °C. Therefore, the microwave technique showed some enhancements in the nutritional value and has the potential to be applied as an effective preservation method of bighead carp fish. Furthermore, dried fillets could be an alternative source of bighead carp fish for the food industry.

Potential of microwave drying technology for increase drying rate and physical quality of kaffir lime (Citrus hystrix DC) leaves

The effects of microwave power on microwave drying rates and the physical quality of kaffir lime leaves were studied. Three power levels were used in this study, high (723 watts), medium (537 watts), and low (420 watts). The moisture content, drying rate, color (L, a, b), and organoleptic parameters of each power level will be compared with the oven drying method (60°C). The result shows that the final moisture content of the high, medium, and low power of microwave drying are 6.06, 4.26%, and 6.16%db respectively, which is lower than oven drying, 16.62%db. Besides, the drying rate of microwave drying is 26.39-48.71%db/minute, higher than oven drying 0.32%db/minute. Dried kaffir lime leaves with medium level power (537 watt) has the lowest color difference (ΔE = 1.0 ± 0.29) compared to fresh leaves. While, the color and aromatic preference test dried kaffir lime leaves by microwave drying was preferable than oven drying.