Oven Drying Research Articles

Modelling convectional oven drying characteristics and energy consumption of dehydrated yam (Dioscorea rotundata) chips

The influence of pre-treatments and different dehydrating temperatures on the drying dynamics, energy consumption, and quality attribute of yam chips was studied. Dehydration was executed employing a convectional oven dryer under four temperatures (50, 60, 70, and 80 °C) and 2.0 m/s air velocity. Yam chips were subjected to pre-treatment conditions of blanching (for 1, 2, 3, 4, and 5 min), citric acid (1 and 5 %), and ascorbic acid (1 and 5 %) solutions whereas, untreated yam chips samples served as the control. Dehydrated yam chips were further assessed for textural and colour properties. The drying rate was found to be faster at a higher temperature of 80 °C compared to lower temperatures of 50, 60, and 70 °C. The asymptotic model was established to be the suitable descriptive model for predicting moisture profile in the pre-treated yam chips based on highest R2 values (0.995–0.999), lowest χ2 values (4.422–18.498), and the root mean square error (RMSE) values (2.103–4.30). Pre-treatment and drying temperature had a significant (p <0.05) impact on the hardness and colour of dehydrated yam chips. Blanching at 4 min yielded yam chips with most preferred texture (hardness: 81.3 N) and lightness (L*) in colour values (71.07 %) after drying compared to other pre-treated samples. The effective moisture diffusivity values of the pre-treated samples were in the range of 5.17294 × 10−9m2/s to 1.10143 × 10−8m2/s for 5 % citric acid samples at 50 °C and all pre-treated samples at 80 °C respectively. The general findings of the study indicated a least energy usage of 43.68 kWh as a cost-effective method of drying. Also, 4 min blanching, 5 % citric acid, and 1 % ascorbic acid at 80 °C were found to be the optimum conditions for pre-treating yam chips based on lower energy level consumption rates and improved sensory properties thus attributing to the quality of the dried yam chips.

Comparison of Murraya microbiological contamination and total flavonoid content on various drying methods

Abstract Kemuning (Murraya paniculata (L.) Jack) is one of the ingredients in Herbal Medicine formulation to treat overweight. The herbal medicine raw materials used must be safe and efficacious. Improper post-harvest handling during the drying process can reduce the quality of simplicia regarding microbial contamination and chemical content. In this study, drying is carried out using several methods, namely sun drying, cabinet oven, room oven, bed dryer, and a combination of drying methods (sunlight-room oven, sunlight-cabinet oven, bed dryer-room oven, and bed dryer-cabinet oven) to determine how the drying methods affect M. paniculata simplicia’s microbial contaminations and the content of total flavonoids. The experimental trial was designed with a randomized block design and three replications. The parameters observed were microbial contamination (Total Plate Count and Total Yeast Mold Count) and the total flavonoid content of simplicia. The F test analyzed and further tested the data with orthogonal contrast using Microsoft Excel. The outcomes demonstrated that various drying techniques had highly diverse impacts on bacterial and fungal contamination of the simplicia. There was a significant difference in the total plate count of simplicia between the single drying method and the combination method. Significant differences in fungal contamination were obtained using the combination method of drying in the sunlight-room oven with the sun-cabinet oven drying. The drying process using a cabinet oven and sunlight-cabinet oven combination produced the highest total flavonoid content. However, drying using a combination method of sunlight-cabinet oven does not meet the requirements in terms of microbial contamination. Drying using the cabinet oven method produces the best quality simplicia regarding safety and efficacy.

Optimizing the extraction of polyphenols from Prunus spinosa L. fruit using response surface methodology and production of powders from optimized extracts by foam mat drying

Prunus spinosa L., commonly known as blackthorn, holds traditional significance both as a food source and an herbal remedy. This study aims to determine the extract that includes the highest total phenolic content (TPC), antioxidant capacity (AC) using DPPH and CUPRAC assays, and vitamin C from blackthorn using the response surface method in an ultrasonic water bath and to this extract into powder by foam mat drying. The investigation comprises two primary phases. Firstly, the impact of temperature (20–80 °C) and extraction time (5–30 min) on TPC, AC, and vitamin C were systematically explored. Subsequently, the extracts derived from blackthorn fruit were subjected to foam mat drying, utilizing two distinct ratios (7:3 w/w and 8:2 w/w) of foaming agents [maltodextrin (MD) to egg white (EW)], along with three drying techniques (oven, microwave, and natural drying). The optimized extraction parameters were determined as follows: temperature (80 °C) and time (30 min). Furthermore, the results reveal that microwave-dried powders with a low EW ratio exhibit superior preservation of TPC, AC, and vitamin C content. This research underscores the potential utility of foam mat-dried blackthorn powders as functional ingredients and natural colorants within the realm of the food industry.

Investigating the Effect of Cumin (Cuminum cyminum L.) Hydroalcoholic Extract on the Incidence of Passive Avoidance Learning in Gonadectomized Male Wistar Rats

Background: Learning and memory are fundamental to the survival of human life. In view of that, a relationship exists between age-related forgetfulness and changes in sex hormone levels. Objectives: Respecting the benefits of cumin (Cuminum cyminum L.) for sex hormones, this study investigated the effect of cumin hydroalcoholic extract (HAE) on learning and memory in gonadectomized (GDX) male Wistar rats. Methods: First, cumin seeds were purchased and identified by the herbarium affiliated with Islamic Azad University (IAU), Qom branch, Qom, Iran. The hydroalcoholic extract (HAE) was then extracted using a Soxhlet apparatus, and cumin powder was prepared using a drying oven. A total of 48 male Wistar rats (weighing 250 ± 50 g) were divided into eight groups: A normal group treated with dimethyl sulfoxide (DMSO), three normal groups receiving cumin HAE doses of 25, 50, and 100 mg/kg, a GDX group treated with DMSO, and three GDX groups receiving cumin HAE doses of 25, 50, and 100 mg/kg. Following the surgical procedure to remove both testes, intraperitoneal (IP) injections were administered. Half an hour later, learning and memory tasks were conducted using the Shuttle box, and the step-through latency (STL) as the standard index of passive avoidance learning (PAL) was recorded for 10 minutes. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test. Results: The GDX male Wistar rats receiving DMSO experienced a significant decline in STL compared to the normal group treated in the same manner (P &lt; 0.001). The rats in the GDX groups receiving cumin HAE doses of 50 and 100 mg/kg also demonstrated a significant increase in STL compared to the GDX group treated with DMSO (P &lt; 0.001). Conclusions: As evidenced, GDX decreased PAL, but cumin HAE boosted learning and memory in the GDX male Wistar rats.

Different drying methods alter the quality parameters of ethnobotanically important Curcuma caesia Roxb. rhizomes

Curcuma caesia Roxb. of the Zingiberaceae family, is an ethnobotanically important rhizomatous perennial herb and is commonly known as “Black turmeric”. Like in other species of Curcuma, the pharmacologically important polyphenol curcumin is also found in C. caesia. In traditional medicine, C. caesia has been used to treat piles, leprosy, asthma, cancer, diabetes, fertility, toothache, vomiting, allergies, etc. Drying is considered the simplest and most cost-effective means of preserving raw plant materials, safeguarding the integrity of nearly all biologically active substances. Medicinal plant materials are primarily utilized in their dried forms in pharmaceutical industries. However, it has been observed that there is a lack of comprehensive information on the effects of different drying methods on quality parameters, and other pharmaceutically important aspects of C. caesia. Hence, here, we investigated the impact of various drying methods, such as direct sunlight exposure, solar drying, shade drying, and conventional oven drying with or without previous boiling, on the quality parameters of C. caesia rhizome, such as moisture, ash, and curcumin content. The results suggest that oven drying at 100 ?C, despite possessing favorable criteria for drug designing like the smallest particle sizes and the lowest moisture content, did not restore the maximum level of ash, curcumin, and essential mineral elements. Nevertheless, boiling in the range of 60 ?C – 80 ?C for 30 minutes before drying restores the pharmaceutically important qualities more favorably. The results of this study will help to formulate better treatment for restoring the market-preferable optimum quality of C. caesia.

Effects of Sun and Oven Drying on The Physicochemical Composition of Indonesian Sandfish (Holothuria scabra)

Sandfish (Holothuria scabra) is a type of sea cucumber with high economic value. Sandfish are potentially used as food, pharmaceutical, and cosmetic ingredients. This research aimed to determine the effects of sun and oven drying on the physicochemical composition of sandfish collected from Pesawaran Waters, Lampung, Indonesia. The physicochemical composition includes the proximate composition, saponin content, collagen content, and metabolite profiles. The sea cucumbers were divided into two groups; the first group was boiled for 30 minutes, whereas the second group was unboiled. The sea cucumbers were oven-dried (temperature 60 °C for 24 h) and sun-dried (3 days from 08:00 a.m. until 5:00 p.m.). Fresh sandfish (without drying) were used as control samples. The dried and fresh sandfish were analyzed for their proximate composition (moisture, ash, fat, protein, and carbohydrates) and collagen content. The dried and fresh sandfish were extracted by maceration using ethanol. The extract was analyzed for its saponin content and metabolite profiles. The results showed no significant differences (p0.05) between oven-dried and sun-dried sandfish regarding their proximate composition and collagen content. However, the saponin content in boiled sandfish extract was significantly different (p0.05) from the saponin content in sandfish extract that was unboiled. The highest saponin content of all treatments was in the boiling and oven-drying treatment (N1P2), i.e., 7.418 mg quillaja/10mg extract. The Fourier Transform Infrared (FTIR) profile indicated that the functional groups in the sandfish extract did not change during the drying process. The findings indicate that oven and sun drying do not negatively affect the physicochemical composition of the sandfish, especially its bioactive compounds, i.e., saponin and collagen.

Effect of Refractance Window™ and oven drying on physicochemical and sensory properties of peach (Prunus persica L.) surplus.

Currently, approximately 34% of fruit is lost and wasted in emerging economies due to inefficient post-harvest processes, technological shortcomings, lesser valorization of surpluses, and byproducts. Peach (Prunus persica L.) is a fruit with a good yearly growth rate but higher postharvest losses in Colombia. One way to take advantage of this type of product is through the application of drying processes that increase its shelf life and its inclusion in the food chain. Refractance Window Drying (RWD) is a fourth generation drying technique implemented by the food industry in the last few decades and has been applied to several dehydrated food products. This study compared the effects of different drying methods on the physical and sensory properties of peaches surplus. Treatments consisted of (i) peaches were sliced (1, 2, and 3 mm thickness) and dried using RWD at 86°C, (ii) peach pulp mixed with maltodextrin (MD) (0.12-0.33 kg of MD/kg of sample) and RWD (RWD-MD), and (iii) conventional oven drying (OD) at 60°C (3 mm thick) dried for 24 h. The study found that the drying method significantly (p < 0.05) affected the texture, color, and general taste of peaches. The results showed that processing treatments combined with different drying conditions affected the physical properties of the peach. RWD in slices reduced water content to 0.05 kg H2O/kg in 40 min, showing fewer effects on color attributes. A surface response analysis on RWD showed good correlations for water activity (R2 = 0.8652-0.9894) and moisture content (R2 = 0.7048-0.9826). A higher diffusion coefficient (1.63 × 10-6 m2 s-1) was observed for RWD in slices with 3 × 10-3 m of thickness; however, for RWD-MD, differences in diffusion coefficients were present for the lowest MD addition (0.12 kg/kg), vitamin C was not detected on the dried slices, and higher concentration of β-carotene (175.88 μg/100 g) was found on the thinner slices. Principal component analysis showed that RWD in the slices was the most suitable drying process, followed by OD. Sensory analysis showed good acceptability for RWD slices after 30 days of storage.

Impact of different drying treatments on the biochemical and antioxidant activity properties of Egyptian red beetroot

This paper aims to provide an overview of the main findings and conclusions of the research on freshly sliced Egyptian red beetroot (Beta vulgaris). Beetroot belongs to the botanical family of Chenopodiaceae and encompasses various variations with bulb hues that span the spectrum from yellow to crimson. It is known that the ethanolic extract from beet contains many health-beneficial and bioactive chemicals, such as alkaloids, carotenoids, phenols, tannins, and flavonoids; it also contains vitamins C, B3, B6, and B9. Hence, the beetroot extract exhibits both antioxidant and nutritional properties. The study was conducted to investigate the effects of two different drying processes, oven-drying (OD) and freeze-drying (FD), on the physicochemical qualities of betalain pigments and antioxidants. Overall, freeze-dried (FD) samples demonstrated superior retention of beetroots proximate composition when compared to those dried in the oven. This was observed in terms of minerals and antioxidants, with freeze-drying resulting in higher levels of these components compared to oven drying. On the other hand, reductions in some phenolic compounds were found in the samples treated with the freeze-drying method when compared with the oven-drying method. It was proven that red beets have a lot of phenolic compounds, including kaempferol, caffeic acid, vanillic acid, gallic acid, catechin acid, rutin, hesperidin, naringin, quercetin, and ferulic acid.

Analysis of the Effect of Trust and Information Sharing on Supply Chain Performance with Innovation as a Mediating Variable (Study on gula semut SMEs in Kulon Progo Regency)

This study aims to determine the effect of trust (X1), information sharing (X2) on supply chain performance (Y) mediated by Innovation SMEs. The population in this study were SMEs in Kulon Progo Yogyakarta. From the population taken 35 samples with non-probability sampling method. The model in this study uses Partial Least Square. And the results showed that trust and information sharing have a significant positive effect on supply chain performance mediated by SME Innovation. Applicative suggestions that can be applied are the need for trust between supply chain members. because there is still distrust between supply chain members which in the future can hinder supply chain performance. In addition, there is a need for innovations that can accelerate the performance of the supply chain such as the need for a sap drying oven, plastic caps so that the sap is not mixed with water and dirt and jerry cans are placed between 4 - 5 coconut trees which makes it easier to transport raw material supplies. With trust and information sharing can create these innovations that can affect supply chain performance.

Combination of Oven and Microwave-assisted Drying Technique for Production of Ready-to-Eat Dried Rice

A combination of oven and microwave was introduced with the purpose of preparing well-balanced dried ready-to-eat dried rice samples. The parameter condition was investigated (oven temperature; 70 and 90 °C, time; 70, 130 and 180 min, microwave power; 450 and 750 W and time; 1, 2, 3, 4 and 5 min). From the study, increasing in moisture content and rehydration capability was obtained when the drying conditions were increased. However, the color product was changing as the color difference was improved whereby the samples with lower water activity have lower microorganism growth (0.4-0.5 wa). The nutrient obtained were in the range of 55.5-65.9% for carbohydrate, 6.4-9.3% for protein, 65.9-17.3% for fat and 3.4-3.5 for ash content, respectively. It can be concluded that the use of oven and microwave in this study is acceptable for preparing ready-to-eat dried rice.

Evaluation of drying and extraction parameters for the extraction yield of watermelon (Citrullus lanatus (Thunb.)) rind using statistical design experiment

Watermelon rind contributes about 30% of overall watermelon mass and is considered the most underutilized resource as it is usually discarded as waste. Watermelon rind resources have great potential economic value in various industries. Thus, utilizing the rind could decrease the amount of biological waste in the environment. Therefore, this study aims to determine the optimal conditions in extracting oven and dehydrator drying watermelon rind using a sonicator extraction procedure. Watermelon rind samples were evaluated using a one-factor-at-a-time (OFAT) evaluation to identify the most significant factor for the sonicator extraction time (0.5-3 hrs), ethanol concentration (20-100%), solvent-tosolid ratio (10:1-50:1 v/w), and sample drying time (24-48 hrs) parameters. The highest yield obtained for the oven drying sample was at one hr extraction time (15%), 100% ethanol concentration (12.5%), 30:1 v/w ratio (12%), and 48 hrs drying (9%). Meanwhile, the extraction yield of dehydrator drying sample was optimized at one hr of extraction time with 10% yield 100% of ethanol concentration with 15.4% yield, 40:1 v/w of solvent ratio with 14.7% yield, and 48 hrs of drying with 8% yield. The optimum extract yield of dehydrator drying sample could be further applied for cosmeceutical application as it produced higher yield compared to oven drying sample.

Effect of Different Drying Methods on the Mineral Composition of Three Indigenous Leafy Vegetables

Leafy vegetables are known to contain high amounts of nutrients and phytochemicals which support growth and development in humans after consumption. Due to their high moisture content at stage of maturity, the rate of perishability is high. The objective of this study was to determine the effect of three drying techniques on the nutritional quality of three indigenous leafy vegetables. The experimental design was a 3x3 factorial arranged in Completely Randomized Design (CRD). The factors were; leafy vegetables at three levels (Amaranthus cruentus, Celosia argentea and Laportea aestuans) and drying methods at three levels (Solar, Oven and Freeze drying). Our results showed that A. cruentus significantly (p &lt; 0.05) had the highest phosphorus (0.79 %), potassium (2.22 %) and magnesium (1.15 %) and C. argentea recorded the least concentrations (0.40, 1.26 and 0.61 %) respectively. The concentration of calcium was in ascending order of A. cruentus &lt; C. argentea &lt; L. aestuans with 2.04 &lt; 2.28 &lt; 3.03 % respectively. Iron and zinc contents were higher in C. argentea than A. cruentus and L. aestuans. Moreover, calcium content in freeze dried vegetables with exception of C. argentea increased as compared to Solar and Oven drying. Also, the concentration of phosphorus was in ascending order of C. argentea &lt; L. aestuans &lt; A. cruentus with 0.44 &lt; 0.60 &lt; 1.04 % respectively for freeze drying. It can therefore be concluded that the three indigenous leafy vegetables are good sources of nutrients and these three drying techniques are for the preservation of their nutrients as well as preventing postharvest losses.

The Effects of Microwave and Oven Drying on Bioactive Compounds Individual Phenolic Constituents and the Fatty Acid Profiles of Bitter Orange, Mandarin and Grapefruit Peel and Oils

The Effects of Microwave and Oven Drying on Bioactive Compounds Individual Phenolic Constituents and the Fatty Acid Profiles of Bitter Orange, Mandarin and Grapefruit Peel and Oils

Comparison of four drying methods in terms of the drying efficiency and physicochemical properties of chicken meat

In this study, four drying methods, including hot air drying (HAD), catalytic infrared drying (CIRD), electric infrared drying (EIRD), and electric oven drying (EOD), are used to prepare dried chicken breast. The study systematically compares the drying efficiencies of the different methods and their effects on physico-chemical properties, pet food applications, energy consumption, and costs. The results show that CIRD and EOD resulted in a better color of the final product, while the EIRD treatment resulted in the highest degree of denaturation of the chicken breast jerky proteins. In terms of chemical properties, the higher malondialdehyde content of CIRD and EIRD (2.77±0.18 mg/kg, 2.63±0.07 mg/kg) indicated higher fat oxidation in IR-treated chicken meat, which is also associated with an increase in the content of free fatty acids. This paper also found that arachidonic, linolenic, and oleic acids are positively correlated with the content of important flavor compounds in the jerky. For pet food applications, it was found that pets prefer CIRD and EIRD products, and energy and cost measurements also indicate that CIRD (4258.74 kJ/kg, 0.94 yuan/kg) is more energy and cost-efficient than other drying methods. The results show that CIRD (4258.74 kJ/kg, 0.94 yuan/kg) is a more energy-efficient and less costly drying method.

Bubbling fluidized bed and oven drying for Turkish coal: a comparative study

ABSTRACT The aim of this study is to compare the changes in the heating value of Turkish coal (Konya-Ilgın) with bubbling fluidized bed drying (BFBD) and oven drying (OD). The changes mentioned at three different temperatures (80-95-110°C) and different moisture contents were investigated. In the tests carried out at three different temperatures using BFBD system, coal drying for 60 minutes produced the dried coal samples with the calorific value of 6300 kcal/kg at 80°C. As a result, a calorific value increase of approximately 53.7% based on initial value was achieved. In the OD system, it increased to 4600 kcal/kg under the same conditions, and at 110°C this value increased to 5250 kcal/kg. This means a 28.0% calorie increase. In the BFBD system, at this temperature value, it reached 6450 kcal/kg, an increase of 57.3% compared to the initial caloric value. Coal drying for 60 minutes produced the dried coal samples with the moisture content 8.9% by BFBD at 80°C. As a result, a moisture decrease of approximately 4.40 times based on initial value was achieved. Under the same conditions, the moisture reduction for OD was 1.33 times. When the temperature value reached 110°C, only a 3.07 times decrease in humidity could be achieved.

Kinetics of Oven Drying of Ocimum basilicum Leaves Harvested at Different Ages of Maturity

Kinetics of Oven Drying of Ocimum basilicum Leaves Harvested at Different Ages of Maturity

Physicochemical and sensory evaluation of lemon grass leaves extracts enriched soy yoghurt from soybeans (Glycine max) milk

AbstractThere are challenges in the utilization of soybean‐based foods due to undesirable associated flavors. This study aimed to prepare soybean based yoghurt with different amounts of lemon grass extract in the ratios of 0, 25, 50, 75, and 100 µL/L of soy yoghurt as shown by Figure 1. The Table 1 and 2 summarized results of different treatments of Soybeans based yoghurt analyzed for protein by Kjedhal method, fats by Soxhlet method, total ash by muffle furnace method. Soluble crude fiber was determined by dry oven method, pH, titratable acidity, syneresis and viscosity, by AOAC method, total phenolic compounds by spectrophotometric method. Sensory analysis was done by effective tests with 10 panelists using five hedonic scale tools. From the study, the results indicate that moisture content range from (89.3 to 89.6%); protein content (5.5−6.8%); fat (2.7−3.6%); total ash (0.43−0.53%); crude fiber (0.06−0.33%) and carbohydrate (0.59−0.93%). The level of pH range from 4.30 to 5.59; viscosity (2.85−3.17 pa.s); titratable acidity, (0.01−0.07 g\L) and synersis (6.44−7.56) and total phenolic compound (8.59−18.40 mg/g). Most of the parameters did not show any significant variations while the pH and total phenolic compounds varied significantly between the treatments. In addition, Figure 2 detailed sensory evaluation results of treatments and that the treatment with highest level of lemon grass extract was the most liked. In conclusion, incorporation of lemon grass extract can help improved the level of phenolic compounds and sensory properties of yoghurt.

Effects of Various Drying Methods on the Proximate Composition and Antioxidant Activities of Stellaria media Leaves

Background: Stellaria media belongs to the family of Caryophyllaceae. The plant is widely distributed in cold and temperate region all over the world. However, different parts of the S. media plant have been used to treat various disorders such as diarrhoea, jaundice, asthma, gastrointestinal disorders, measles, renal, reproductive, digestive, and respiratory tracts inflammations. Aims: This investigation is aimed to determine the proximate composition and antioxidant activity of S. media leaves by using three different drying methods- Sun drying (SD), Shadow drying (SHD), and Oven drying (OD). Methodology: All the experiments were performed according to standard procedures of the Association of Analytical Communities (AOAC). In this study, the effect of drying method on the proximate composition, mineral content, and antioxidant activity such as total flavonoid content, DPPH, and FRAP were investigated. Results: The result was compared with the fresh leaves (FL) of the S. media. FL of S. media was recorded to have maximum amount of moisture content. Also, the ash content which was determinant of minerals content was higher in OD sample compared with the FL and other drying methods. Protein and crude fiber were higher in dried samples as compared with the FL. Furthermore, levels of calcium (Ca) and iron (Fe) were higher in SD sample as compared with FL, SHD, and OD samples. Meanwhile, the total flavonoid content (TFC) 652.0±0.56 mg quercetin/g was highest present in OD sample in methanol extract. The inhibition percentage in DPPH ranged from 4.8±0.17 in FL in water extract to 95.8±0.21 in OD samples in methanol extract. The value of FRAP ranged from 9.0±0.42 µmol FeII/g in FL in water extract to 9277.0±0.33 µmol FeII/g in OD samples in methanol extract. Also, the result showed in both DPPH and FRAP highest value in OD sample in methanol extract as same as TFC. Conclusion: Nutrients and antioxidants help to maintain the nutritional status as well as to prevent various diseases. Therefore, they should be included as a dietary supplement. Furthermore, this represents a driver for future research in this field to consider different drying methods and determine the change in antioxidant activity using the high-performance liquid chromatography (HPLC) method.

Effect of Sarcoplasmic Protein Solutions Dried at Different Times and Rates on Water Migration in Lamb Myofibril In Vitro.

To determine whether sarcoplasmic proteins affected water migration in myofibrils during air-drying, with protein denaturation as an indicator of sarcoplasmic protein changes, the extent of sarcoplasmic protein changes in lamb during air-drying was first studied. The results showed that sarcoplasmic protein's thermal stability decreased and secondary structure changed, indicating sarcoplasmic protein denatured in lamb during air-drying (35 °C, 60% RH, 3 m/s wind speed). Subsequently, the effect of sarcoplasmic protein solutions, dried at different times and rates, on myofibril protein-water interaction was studied in vitro. Two sets of sarcoplasmic protein solutions were dried for 0, 3, 6, and 9 h in a drying oven, resulting in different degrees of change. These two sets with higher or lower drying rates were achieved by controlling the contact area between sarcoplasmic protein solution and air. These dried sarcoplasmic protein solutions were then mixed with extracted myofibril and incubated for 2 h. The results showed a significant increase in T21 relaxation time of the incubation system when sarcoplasmic protein solution was dried at 35 °C for 3 h. This indicated that myofibrillar protein-water interaction was weakened, facilitating water migration from the inside to the outside of myofibrils. The denaturation degree of sarcoplasmic proteins was slowed by a higher drying rate, thereby alleviating the increase in the amount of immobile water within myofibrils when dried for 6 h. In conclusion, the properties of sarcoplasmic proteins were influenced by both drying rate and time, thereby influencing the water migration within myofibrils during air-drying.

Influence of Air Drying, Freeze Drying and Oven Drying on the Biflavone Content in Yellow Ginkgo (Ginkgo biloba L.) Leaves

Drying herbs is a crucial method for stabilizing and preserving their essential properties and bioactive compounds. Although freeze drying is the preferred method for most herbs, it is expensive due to high energy consumption and operating costs. Biflavonoids are dimeric flavonoids that have recently been recognized as potential molecules possessing biological activities, such as antiviral and antimicrobial activity, and as effective molecules for the treatment of neurodegenerative and metabolic diseases and for cancer therapies. In this study, we performed a comparative analysis of freeze drying, air drying and oven drying to evaluate their effects on biflavonoid content in yellow ginkgo leaves (Ginkgo biloba L.). After drying, we performed spectrophotometric analysis to determine the browning index, pigments, phenolic compounds and antioxidant activity, while HPLC-DAD was used for the identification and quantification of individual biflavones (amentoflavone, bilobetin, ginkgetin, isoginkgetin and sciadopitysin). The most abundant biflavonoids were isoginkgetin and bilobetin, the amounts of which exceeded 1000 µg/g dw in all leaf samples. They were followed by ginkgetin and sciadopitysin, the amounts of which were about 30% lower. The drying method did not influence biflavone content or the total carotenoids, total polyphenols and total flavonoids. Consequently, our study suggests that all three methods may be used for the preparation of yellow ginkgo leaves as a source of biflavones and other bioactive compounds.