Osmotic, osmovacuum, sonication, and osmosonication pretreatment on the infrared drying of Ginkgo seed slices: Mass transfer, mathematical modeling, drying, and rehydration kinetics and energy consumption.

This study evaluated the mass transfer, drying, and rehydration kinetics (drying and rehydration curve, moisture diffusivity [Deff ]), energy consumption (specific energy consumption [SEC], moisture extraction rate (MER), and specific moisture extraction rate [SMER]), and mathematical modeling of infrared dried Ginkgo biloba seed (GBS) using the various nonthermal pretreatments namely: osmotic (OS), osmovacuum (V + OS), ultrasound (US, ginkgo seed immersed in a distilled water with US), and osmosonication (US + OS, ginkgo seeds immersed in an OS solution with US). Results showed that various pretreatments affected mass transfer, drying, and rehydration characteristics, and energy consumption, which was confirmed by principal component analysis. In terms of mass transfer, US pretreatment recorded the highest weight loss while the osmosonication pretreatment registered the highest solid gain. The entire drying process occurred in the falling-rate period. The Deff values were within the normal range of agroproducts (10-11 to 10-8 m2 /s). The modified Page-I and Weibull model best fitted the drying and rehydration kinetics, respectively, with the coefficient of determination (R2 ) > 0.991, root mean square error, residual sum of squares, and reduced chi-square closer to zero, compared with the other models. The untreated GBS (control) had the lowest energy efficiency (lowest SMER and MER) and the highest SEC than the pretreated GBS. Among the various pretreatments, the US pretreatment of GBS was superior, with the highest Deff , MER, SMER, and drying rate, and lowest drying time and SEC. Based on the findings, sequential US pretreatment and infrared drying is a feasible drying technique for GBS that could be used commercially. PRACTICAL APPLICATION: Ginkgo tree cultivation in China has exceeded market needs with 60,000 tons per annum of GBS produced. Hence, there is a compelling need to explore new chances to use GBS availability irrespective of the seasonality and address the problem where GBS utilization is limited to the early phases of home-cooked dishes. Although drying increases the shelf life of ginkgo seeds, there is a higher operation cost. Thus, pretreatment can reduce energy consumption and augment the product quality is ideal. This research reported the impact of nonthermal pretreatments on ginkgo seeds' mass transfer, drying, and rehydration characteristics. The present results will provide a comprehensive understanding of the engineering application of ginkgo seed pretreatment, allowing for the best technique to be selected.

Boateng ID ，Yang XM 《-》

Non-thermal pretreatment affects Ginkgo biloba L. seed's product qualities, sensory, and physicochemical properties.

Drying plays a significant role in Ginkgo biloba seed's (GBS) processing, and the previous research showed drying affected the product quality. A combined hurdle drying technology (integrated non-thermal pretreatment and drying) could be applied on GBS to achieve better product quality. Osmotic (OS), osmo-vacuum (OS + V), sonication (US), and osmosonication (OS + US) pretreatment followed by infrared drying was performed on GBS, and the product qualities (texture, color, enzyme inactivation, water activity, and microstructure), physicochemical properties (titrable acidity, reducing sugar, soluble solids, total sugar, free amino acid, and ascorbic acid), and organoleptic qualities were evaluated. Results showed pretreatment had various effects on physicochemical and product quality, and was confirmed by principal component analysis (PCA). The sensory scores, acceptability index combined with Pearson's correlation, and PCA showed that different pretreatments influenced the likeness and acceptability, and color, taste, and odor were the key determinants and strongly associated with the consumers' preferences. The untreated GBS (no pretreatment before drying) had a higher color change and lower enzyme inactivation. Pretreatment increased texture preservation after thermal processing, although it had a negative effect on soluble solids, reducing sugar and total sugar content. While the US improved the texture, it resulted in shrinkage (from the microstructure) and total sugar degradation. Among the various hurdle technologies, osmosonication (OS + US, followed by infrared drying) had the highest sensory attributes, free amino acid, slight structure deformation, and lowest water activity. The present study showed that osmosonication is a promising hurdle technology for GBS because it provides better quality attributes. PRACTICAL APPLICATION: Previous research showed that Ginkgo biloba seed (GBS) drying has an impact on product quality, which will ultimately determine GBS acceptance. This research was set out to envisage and advance current dryer design by merging the sequential operations (integrated non-thermal pretreatment and drying), also known as hurdle drying technology on GBS, to achieve better process efficiency, product quality, and make GBS's drying process more sustainable. The various pretreatments improved ginkgo seed's product qualities compared to the control (no pretreatment prior to drying). Osmosonication is a promising hurdle technology for GBS processing.

Boateng ID ，Zhang W ，Li YY ，Saalia FK ，Yang XM ... -  《-》

Sonication, osmosonication and vacuum-assisted osmosonication pretreatment of Ghanaian garlic slices: Effect on physicochemical properties and quality characteristics.

This work aimed to assess the impact of sonication (US), osmosonication (US + OD) and vacuum-assisted osmosonication (V + US + OD) pretreatments on the quality of Ghanaian garlic prior to relative humidity convective drying. Hence, slices of fresh garlic subjected to US, US + OD and V + US + OD pretreatments were dried and the following assessed: antioxidant activities, total phenolic content (TPC), total flavonoid content (TFC), polyphenol oxidase (PPO) enzyme inactivation, rehydration ratio (RR), drying kinetics, energy consumption, chromatographic fingerprinting, allicin content and Fourier-transform infrared (FT-IR) spectroscopy. V + US + OD pretreatment gave the best results for antioxidant activities, TPC, TFC, RR and PPO enzyme inactivation. It also recorded the shortest drying time and was more energy efficient. Finally V + US + OD pretreatment maintained the chemical integrity of the finished product and recorded the highest content of allicin. A general trend was however observed for all quality parameters assessed for the various pretreatment methods as: V + US + OD > US + OD > US.

Alolga RN ，Osae R ，Essilfie G ，Saalia FK ，Akaba S ，Chikari F ... -  《-》

Effects of Various Nonthermal Pretreatments on the Physicochemical Properties of Dried Ginger (Zingiber officinale Roscoe) Slices from Two Geographical Locations.

This study explored the effect of different nonthermal pretreatments, osmosonication (OS), osmotic dehydration, and ultrasound methods on the physical and chemical properties of China- and Ghana-sourced ginger samples under relative humidity convective drying. The chemical properties of pretreated dried ginger slices were assessed for antioxidant properties (ABTS and DPPH); total phenolic content; total flavonoids content; and 4-, 6-, 8-, and 10-gingerol and 6-shogaol levels. The physical properties compared were weight loss, rehydration ratio (RR), texture, and drying kinetics. Results revealed that OS pretreatment led to a higher preservation of the chemical properties with the Ghana-sourced ginger exhibiting the highest values. The OS-treated samples obtained the highest weight losses and RRs, but the RR was higher in the Chinese ginger. OS pretreatment also gave the lowest textural value with the China-sourced samples exhibiting the lowest firmness. Weibull model best fitted the experimental results (R2 > 0.99). PRACTICAL APPLICATION: Ginger remains among the most notable medicinal spices worldwide. It is used as a raw material for the pharmaceutical, beverage, cosmetics, and the food industries. Long-term storage of ginger is one of paramount importance, hence any pretreatment that reduces its moisture content and lessens its drying time but preserves its quality is ideal. In this study, we report the effect of different nonthermal pretreatments, osmosonication, osmotic dehydration, and ultrasound on the physical and chemical properties of China- and Ghana-sourced ginger samples under relative humidity convective drying. The present findings will offer more information in the selection of the best pretreatment technique for drying ginger.

Osae R ，Zhou C ，Alolga RN ，Xu B ，Tchabo W ，Bonah E ，Alenyorege EA ，Ma H ... -  《-》

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.

Osae R ，Zhou C ，Xu B ，Tchabo W ，Tahir HE ，Mustapha AT ，Ma H ... -  《-》