The kinetics and thermodynamics study of bioactive compounds and antioxidant degradation of dried banana (Musa ssp.) slices using controlled humidity convective air drying

Effect of convective drying temperature and tray load density on bioactive compounds, antioxidant properties, and functional quality of radish Sango microgreens

This study examined the effects of convective drying parameters, including temperature (40, 50, and 60 °C) and tray loading density (0.057 and 0.113 g/cm2), on the bioactive compounds, antioxidant properties, and structural characteristics of radish sango microgreens powder. Drying at 50 °C with 0.057 g/cm2 preserved the highest anthocyanins (43.23 μmol/100 g), phenolics (189.45 mg GAE/100 g), and antioxidant activities (DPPH 43.13 %, and FRAP 10.80 μmol TE/g), while drying at 50 °C with 0.113 g/cm2 preserved the highest flavonoids (5.86 mg QUE/100 g) and ascorbic acid (239.18 mg/100 g) of radish sango microgreens. Degradation kinetics followed a first-order model, with thermal sensitivity varying among compounds. FTIR analysis revealed functional groups linked to bioactive compounds, while SEM showed flake-like particles enhancing solvent interaction. These findings highlight the significance of controlled drying in retaining functional and structural qualities, supporting the potential of radish sango microgreens in functional food and pharmaceuticals applications.

Drying kinetics and mathematical modeling of coconut meat slices: Insight into pretreatment and drying synergic effect

Coconut consumption provides nutritional and health benefits to humans. Yet, poor postharvest and preservation methods result in the loss of coconut fruit bunches yearly. Investigations into achieving drying techniques that result in optimum drying rates coupled with consumer's desired end products that are both commercially and nutritionally viable remain paramount in the food industry. Consequently, osmotic dehydration is commendable for its low-cost pretreatment merit. Therefore, the study examined the drying-kinetics, energy consumption, effective moisture diffusivity (D eff ), vitamin C retention, color, and rehydration behavior of coconut cultivars (Sri Lanka Green Dwarf × Vanuatu Tall (SGD × VTT), Catigan (CAT), and Tacunan Green Dwarf (TGD)) meat slices. Samples were osmotically pretreated with sucrose solution (30 %/30 min) and subjected to oven drying (80, 90, 100, and 110 °C (air velocity of 2 m/s) and lyophilization (-45 ± 2 °C) methods. A mathematical model was employed to predict the effect of osmotic pretreatment on drying dynamics and the assessment of utilized energy, vitamin C content, color, and rehydration of coconut meat slices at different drying conditions. The oven-dried sample's color changed (p < 0.05) compared to lyophilized samples. Drying-kinetics models were validated using determination coefficient (R2) and root mean square error (RMSE). The Asymptotic model satisfactorily suited the samples' drying data goodness fitting based on R2 ≥ 0.90 - 0.99 and low RMSE ≤ 0.01 - 0.12 compared to other models for both drying methods. D eff ranged between 1.10 × 10-07 m2s-1 and 7.90 × 10-08 m2s-1 for all the drying methods. CAT sample retained high vitamin C content compared to SGD × VTT and TGD samples. Rehydration ratio values were significant at lower temperatures among oven-dried experimental samples whereas TGD samples exhibited a significant rehydration values compared to SGD × VTT and CAT lyophilized samples. Among the drying methods, oven drying exhibited low energy consumption with shorter drying time and optimum D eff per adopted temperature ranges compared to lyophilization. The study revealed that temperature, time, the sucrose solution, and the thickness of the coconut slices strongly influenced the drying kinetics of the osmotically pre-treated coconut meat slice's drying features.

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.

Drying kinetic, thermodynamic and quality analyses of infrared drying of truffle slices

Kinetic and thermodynamic parameters are the most important part for making a suitable tool for drying agricultural products. Moreover, calculation of the energy required for the drying of product, the properties of the rehydration ratio, the food appearance changes, and the evaluation of the microstructure of food are crucial. Since the thermodynamic properties of truffle slices have not yet been reported, this study aims to establish a mathematical model to describe drying process of agriculture product, evaluate the effective moisture diffusion coefficient (Deff), determining the activation energy (Ea) to elucidate the thermodynamic characteristics, measure color characteristics, and rehydration ratio (RR) during the drying process of truffle slices. Truffle slices were dried in an infrared (IR) dryer at four temperatures of 50-80°C and two thicknesses of 0.5 and 1 cm. The best model to describe the drying process of truffle slices was Midilli et al.'s model. The value of Deff, SEC, and RR were in the range of 3.06 × 10-8 to 2.48 × 10-7 m2/s, 79.68-191.271 kWh/kg, and 5.99-7.49, respectively. The Deff of truffle slices increased with the above-mentioned parameters of the samples. The Ea obtained was 26.62-27.43 kJ/mol. The results indicated that enthalpy and entropy decreased with increasing drying temperature, while Gibbs free energy improved. The enthalpy, entropy, and Gibbs free energy values changed between 24.48-25.28 kJ/mol, -130.47 to -122.63 J/mol °K, and 63.97-70.17 kJ/mol, respectively. In addition, the results of color attributes decreased with increasing temperature, while chroma oppositely increased.

Quality Evaluation and Browning Control in the Multi-Stage Processing of Mume Fructus (Wumei)

The dried Mume Fructus (MF), called Wumei in China, is a unique food with medicinal and edible effects. But its actual production method is outdated with low efficiency and inconsistent quality. This study systematically investigated the influence of moisture content (MC), temperature, and relative humidity (RH) on the browning reaction and quality characteristics of the MF and proposed a continuous processing strategy of the three-stage variable process for MF production based on the precise process control of the temperature and the RH. The production process of MF was divided into three stages: preliminary dehydration, browning, and drying. The results showed that the browning reaction rate and drying efficiency were optimal when the MC of the raw materials was reduced to 50%. In the browning stage, the degree of browning was better, and the antioxidant capacity reached the maximum of 64.38 mg/g DM under a processing temperature of 80 °C and an RH of more than 60%. As the RH increased, the drying rate decreased, and the ash content exhibited an increase. Therefore, the optimal processing parameters for the browning stage were determined to be a temperature of 80 °C and an RH of 60%. In the final drying stage, a temperature of 60 °C coupled with a dehumidification mode proved sufficient to ensure efficient drying without compromising the quality of the MF. This study revealed the reaction mechanism of the rapid browning processing of MF, which has important guiding significance for the rapid processing of browning foods.

A review of solar and solar-assisted drying of fresh produce: state of the art, drying kinetics, and product qualities

Global demand exists for high-quality fresh produce. Nevertheless, the quality of fresh produce is severely impacted by its perishability due to its high moisture content. Therefore, fresh produces are preserved using artificial dryers (hot-air dryers, catalytic infrared dryers, etc.) driven by electricity or natural fuels. Nonetheless, the exorbitant cost of power has heightened the need for sustainable resources, notably solar energy, for drying. Hence, this article is a review of how solar dryers and solar-assisted dryers have affected the drying kinetics and quality of fresh produce in the last 5 years. The review showed that solar drying modeling technology (thin-layer modeling, computational fluid dynamics, adaptive-network-based fuzzy interference system, artificial neural network) helps examine fresh produce drying characteristics using various simulation tools before developing any procedure. Solar-assisted drying shortens drying times and increases drying rates. Besides, the quality of the dried fresh produce (color, aroma, appearance, rehydration, etc.) should always be considered. Hybrid solar drying produces higher drying rates and product quality than other solar dryers. However, energy analysis needs to be done as several studies have recognized energy efficiency and product quality. In addition, fresh produce must be pre-treated before solar drying to maintain the final product quality. Therefore, future studies should focus on creating other pretreatment techniques to produce the needed chemical and physical changes and enhance mass and heat transfer. Finally, the influence of solar drying on the final products' nutrient retention or loss, functionalities, or sensory characteristics needs further investigation and comparison to other non-solar drying technologies. © 2023 Society of Chemical Industry.

Nutraceutical Difference between Two Popular Thai Namwa Cultivars Used for Sun Dried Banana Products

Musa (ABB group) “Kluai Namwa” bananas (Musa sp.) are widely grown throughout Thailand. Mali Ong is the most popular Kluai Namwa variety used as raw material for sun-dried banana production, especially in the Bangkratum District, Phitsanulok, Thailand. The sun-dried banana product made from Nanwa Mali Ong is well recognized as the best dried banana product of the country, with optimal taste compared to one made from other Kluai Namwa varieties. However, the production of Mali Ong has fluctuated substantially in recent years, leading to shortages. Consequently, farmers have turned to using other Kluai Namwa varieties including Nuanchan. This study investigated the nutraceutical contents of two popular Namwa varieties, Mali Ong and Nuanchan, at different ripening stages. Nutraceuticals in the dried banana products made from these two Kluai Namwa varieties and four commercial dried banana products were compared. Results indicated that the content of moisture, total sugar, and total soluble solids (TSS) (°Brix) increased, while total solids and texture values decreased during the ripening stage for both Kluai Namwa varieties. Rutin was the major flavonoid found in both Namwa Mali Ong and Nuanchan varieties ranging 136.00−204.89 mg/kg and 129.15−260.38 mg/kg, respectively. Rutin, naringenin, quercetin and catechin were abundant in both Namwa varieties. All flavonoids increased with ripening except for rutin, gallocatechin and gallocatechin gallate. There were no significant differences (p < 0.05) in flavonoid contents between both varieties. Tannic acid, ellagic acid, gallic acid, chlorogenic acid and ferulic acid were the main phenolic acids found in Mali Ong and Nuanchan varieties, ranging from 274.61−339.56 mg/kg and 293.13−372.66 mg/kg, respectively. Phenolic contents of both varieties decreased, increased and then decreased again during the development stage. Dopamine contents increased from 79.26 to 111.77 mg/kg and 60.38 to 125.07 mg/kg for Mali Ong and Nuanchan, respectively, but the amounts were not significantly different (p < 0.5) between the two Namwa varieties at each ripening stage. Inulin as fructooligosaccharide (FOS) increased with ripening steps. Production stages of sun-dried banana products showed no statistically significant differences (p < 0.05) between the two Namwa varieties. Therefore, when one variety is scarce, the other could be used as a replacement in terms of total flavonoids, phenolic acid, dopamine and FOS. In both Namwa varieties, sugar contents decreased after the drying process. Sugar contents of the dried products were 48.47 and 47.21 g/100 g. The drying process caused a reduction in total flavonoid contents and phenolic acid at 63−66% and 64−70%, respectively. No significant differences (p < 0.05) were found for total flavonoid and phenolic contents between the dried banana products made from the two Namwa varieties (178.21 vs. 182.53 mg/kg and 96.06 vs. 102.19 mg/kg, respectively). Products made from Nuanchan varieties (24.52 mg/kg) contained significantly higher dopamine than that from Mali Ong (38.52 mg/kg). The data also suggest that the banana maturity stage for production of the sun dried products was also optimum in terms of high nutraceutical level.

Degradation kinetics of carpaine and antioxidant properties of dried Carica papaya leaves as affected by drying methods

Carpaine in papaya leaves has the potential to treat dengue fever and it also contains antioxidants which could prevent or inhibit oxidation processes in the human body. Studies were conducted on the effects of storage on carpaine retention and antioxidant properties of dried papaya leaves. Results showed that the Weibull model could predict well the degradation kinetics of carpaine in all samples (freeze drying and hot air drying at 60 °C and 70 °C) except for hot air dried samples at 80 °C and shade dried samples (first order model). Generally, freeze dried samples showed the highest half-life whereas total polyphenols content and antioxidant properties (ABTS and DPPH free radical scavenging activities) of all dried samples decreased with storage period. An increasing trend in total colour difference (ΔE * ) was observed in all samples possibly due to chlorophyll degradation. It is thus recommended to select freeze dried samples for storage purpose due to better stability as indicated by the lowest rate constant (k = 0.0135 1/month) and the highest half-life (t 1/2 = 51.2 months).

Systematic Review: Heat Treatments on Phenolic Content, Antioxidant Activity, and Sensory Quality of Malaysian Mushroom: Oyster (Pleurotus spp.) and Black Jelly (Auricularia spp.)

Pleurotus spp. and Auricularia spp. are popular species consumed by the Malaysian community. Recently, due to increased awareness, both mushrooms are also being consumed for their bioactive compounds, ergothioneine, and antioxidant properties and has been used since earlier ages as therapeutic remedies. The bioactive compounds such as phenol, flavonoid and ergothioneine found in both Pleurotus and Auricularia mushrooms were explored. Differences in heat treatments (microwave, hot air drying, and solar drying) and cooking methods may affect the content of bioactive compounds and their properties. Similarly, sensory acceptance by consumers may be affected too. Antioxidant properties using DPPH (1,1-diphenyl-2-picryl-hydrazyl) radical and FRAP (ferric reducing antioxidant power) assay of both raw and heat-treated mushrooms are included. Microwave drying retained color characteristics and bioactive compounds in both mushrooms. To add value to this review, a survey on the consumption pattern of Pleurotus and Auricularia species among Malaysians has been conducted online and concluded that Pleurotus species is the most considered species compared to Auricularia mushroom and almost half of the respondents were not aware that heat may deplete nutritional contents in mushroom despite agreeing both gave beneficial health in diets.

Bioactive's Characterization, Biological Activities, and In Silico Studies of Red Onion (Allium cepa L.) Skin Extracts

This study aimed to investigate the thermal stability and biological activities of the phytochemicals from the red onion skins extract, which are a rich source of anthocyanins. Eight anthocyanins were identified in the extract by high-performance liquid chromatography, the most abundant ones being cyanidin 3-O-laminaribioside and cyanidin 3-O-(6″-malonoyl-laminaribioside). The study also involved the assessment of the thermal degradation kinetics of anthocyanins and antioxidant activity in the 75-155 °C temperature range. The thermal degradation kinetics was described using the first-order kinetics model. In terms of thermal stability, increasing the temperature resulted in lower half-life values (t_1/2) and higher degradation rate constant values (k) for both anthocyanins and antioxidant activity. The thermodynamic parameters revealed that the phytochemicals' degradation is a non-spontaneous and endothermic reaction. Furthermore, the inhibitory effect of the extract was investigated against the enzymes affiliated with metabolic syndrome, oxidative stress, and inflammatory process diseases. Thus, we also demonstrated that the red onion skins extract exerted inhibitory activity on α-glucosidase, α-amylase, lipase, and lipoxygenase. Considering the high content of bioactives and various biological properties, the red onion skins extract is suitable for multiple applications.

Mitigation of relative humidity (RH) on phytochemicals and functional groups of dried pineapple (Ananas comosus) slices

As part of finding a mechanism to ameliorate the decomposition of phytochemicals and antioxidant in drying processing, this research was conducted. To achieve this, pineapple slices was dried using relative humidity (RH) dryer at varied temperature (60–80 °C) combined with RH (10–30%) conditions. The results revealed that higher RH retained with significantly difference (p <0.05) the phytochemical and antioxidant concentrations and preserved the color and functional groups of dried pineapple under varying drying temperatures. The result also shows that concentrations of these compounds may differ as a result of disparities in the chemical composition which may be worsening by drying conditions such as higher temperature and lower RH. In effect, RH could savage the intensity of losses of these compounds and could therefore play a critical role in drying technology. Practical application: The loss of phytochemicals including polyphenols and antioxidant remains one of the challenging phenomena in drying technology. This research finds ameliorative option for mitigating against the loss of polyphenols and antioxidant by exploring the use of relative humidity (RH). The result shows that RH could savage the intensity of loss of these compounds and could therefore play a critical role in drying technology.

Storage effects on the quality quartet of orange juice submitted to moderate thermosonication: Predictive modeling and odor fingerprinting approach

The effects of moderate thermosonication (MTS) on the quality quartet: physico-chemical, microbial, nutritional and sensory qualities of orange juice (OJ) inoculated with Alicyclobacillus acidoterrestris (AAT) were studied during 24 days of storage at ambient and refrigerated temperatures. The bioactive compounds and antioxidant activity of OJ decreased with storage, while the pectin methyl esterase (PME) increased. Nonetheless, noticeable changes were observed from the 12th day of storage. There was no obvious (p > 0.05) variation in pH and total soluble solids. To determine the nutritional and microbial quality characteristics of OJ during storage, non-linear kinetic curves were successfully fitted with least square fitting polynomial and four-parameter log-logistic distribution models. The E-nose sensors succeeded in discriminating between the aroma of non-treated and treated OJ based on linear discriminant analysis (LDA). Furthermore, terpenes, alcohol and partially aromatic compounds were the main spoilage indicators of OJ during storage based on E-nose analysis and confirmed by HS-SPME-GC/MS analysis. Thus, MTS significantly extended the shelf life of the quality quartet of natural OJ at 4 °C. E-nose-GC/MS fusion offered odor fingerprints to AAT microorganisms that can be used as spoilage index without using traditional food analysis techniques. The proposed approach can be used as an alternative tool for rapid detection of spoilage microorganisms in OJ.

Application of non-thermal pretreatment techniques on agricultural products prior to drying: a review

BACKGROUND

Most agricultural crops contain high moisture content (80-95% wet basis (wb)) which makes them very susceptible to microbial damage leading to shorter shelf-life and high postharvest losses. The high perishability of these agricultural products requires preservation techniques to prolong their shelf-lives. Drying remains an important component of processing in this regard. Therefore, any pretreatment methods for drying agricultural product that decreases the moisture content and minimizes drying time by conserving the quality of the crop product is of prime significance. This article is a comprehensive review of recent developments of non-thermal pretreatment (NTP) methods. A summary of their significance, emerging and innovative methods of this technology together with its applications and limitations are discussed. This article further examines the environmental impact of NTP techniques.

RESULTS

NTP techniques, such as high pressure, ultrasound, pulsed electric field and osmotic dehydration methods are essential operations for pre-dehydration of agricultural products prior to drying. These techniques can avoid the deleterious effects of heat on nutritive value, colour and flavour of agricultural products compared to thermal pretreatments. They also enhance the inactivation of the enzymes, improve energy efficiency and mass transfer, reduce processing time, preserve bioactive compounds, improve drying kinetics and drying rate, minimize enzymatic browning, and enhance product quality.

CONCLUSION

These findings will provide a better understanding of different NTP methods and also make available more information for selecting pretreatment techniques for drying of agricultural products. © 2020 Society of Chemical Industry.

Shelf-life extension of grape (Pinot noir) by xanthan gum enriched with ascorbic and citric acid during cold temperature storage

The detrimental health implications of chemical preservatives in fruits have necessitated exploitation of safe and natural alternatives such as edible gums. This work studied shelf-life extension in grape (Pinot noir) under cold storage by xanthan gum (XAN) coatings enriched with ascorbic acid (XANAS) and citric acid (XANCI). Standard scientific methods were used to examine some sensory (color, texture-resilience and hardness), enzyme, anthocyanine and antioxidant activities. Also, the reaction rate mechanism was examined through modeling of selected shelf-life indicators; color change, weight loss, and antioxidants. The results revealed that, Xanthan gum and its acid modified coatings significantly (p < 0.05) suppressed polyphenol oxidase, ascorbic acid oxidase, polymethyl etherase acitivies and maintained the structural integrity of the grape during the 21 days storage period. Weight loss (%) in the grape samples was 13.66 < 13.98 < 14.16 < 15.64 in the order XANAS < XANCI < XAN < CONTROL whilst ferric reducing antioxidant power (FRAP) activity was 150.23 > 143.18 > 136.49 > 104.5 mg/100 g AEAC corresponding to XAN > XANAS > XANCI > CONTROL. Significantly (p < 0.05) higher phytochemical contents were observed in the gum coatings compared to the control. Through statistical parameters such as the coefficient of determination (R ²), root mean square error (RMSE) and reduced Chi square (χ²), the second-order polynomial model predicted precisely the decomposition of color, weight loss and FRAP of grape. Color deterioration was attributed to changes in b* parameter as a result of phenolics and phytochemical decompositions resulting from enzymatic activities. Conclusively, acid modified xanthan gum coatings could preserve phytochemicals, color, antioxidant and textural properties of grape in cold temperature storage.

Effects of ultrasound, osmotic dehydration, and osmosonication pretreatments on bioactive compounds, chemical characterization, enzyme inactivation, color, and antioxidant activity of dried ginger slices

The effect of ultrasound (US), osmotic dehydration (OD), and osmosonication (OS) pretreatments on total phenolic content (TPC), total flavonoids content, (TFC), phytochemical constituents (gingerol derivatives and diarylheptanoids), polyphenol oxidase (PPO), peroxidase (POD), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), cupric ion reducing capacity (CUPRAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power capacity (FRAP), and color of ginger slices dried under relative humidity convective dryer was investigated. OS pretreatment improved the preservation of TPC (13.80-34.79 mg GAE/g d.w), TFC (26.46-62.16 mg CE/g d.w), ABTS (30.37%-86.10%), CUPRAC (36.89-73.97 mg/g), DPPH (50.57%-92.60%), FRAP (26.44-83 mg/g), and phytochemical constituents than US and OD. The OS-treated sample was more effective in inactivating both PPO (12.09%-35.93%) and POD (16.21%-39.58%) enzymes compared to US and OD-treated samples. However, US pretreatment retained the color quality of dried ginger slices than the OS and OD treatments. OS pretreatment (5.43) also increased the total color change (ΔE) of the dried ginger samples compared to US (2.81) and OD (4.60). PRACTICAL APPLICATIONS: Ginger is commonly used in the food, beverage, and pharmaceutical industries owing to their distinctive flavor and various health potentials. However, its high moisture content makes its inappropriate for long-term storage which results in its high perishability. Drying is one of the most common techniques to prolong its shelf life. Hence, any pretreatment for ginger that reduces the moistures content and lessens the drying time by preserving the quality of the crop is of vital importance. Ultrasound, osmotic dehydration, and osmosonication are novel pretreatment techniques that are widely used prior to drying of various agricultural products due to its numerous advantages over conventional methods. Its application in drying of foods could help shorten the drying time, reduce processing costs, improve energy consumption and efficiency, and preserve the physical and nutritional properties of the dried product. The current findings will also offer more information for selecting pretreatment techniques for ginger drying.

Modeling of drying and ameliorative effects of relative humidity (RH) against β-carotene degradation and color of carrot (Daucus carota var.) slices

Drying and β-carotenes retention kinetics were predicted using models in relative humidity (RH) drying condition. This was achieved by drying carrot slices using RH-convective hot-air dryer at 60, 70 and 80 °C under RH (10% 20% and 30%) conditions at 2.0 m/s air velocity. Three mathematical models describing thin layer were compared to their goodness of fit in terms of coefficient of correlation (R²), root mean square error (RMSE) and reduced Chi square ( χ 2 ). The Wang and Singh model could satisfactorily describe RH-convective drying of carrot slices with R², RMSE and χ 2 in the ranges of 0.996-0.999, 5.4 × 10^-4-9.4 × 10^-4 and 0.0150-0.03353 respectively. The results reveal that a range of 3.61-8.2% retention of β-carotene was observed for every 10% increase in RH in various drying air temperature. In summary, higher temperatures were mainly responsible for β-carotenes degradation however this can be mitigated when drying is conducted under higher RH.