Valorization of cashew nut testa phenolics through nano-complexes stabilized with whey protein isolate and ß-cyclodextrin: Characterization, anti-oxidant activity, stability and in vitro release.

Cashew nut testa (CNT) is an underutilized cashew by-product rich in polyphenols. The applications of CNT are limited due to its astringency, less solubility, and instability of polyphenols during the processing. Nanoencapsulation was used to overcome these limitations. ß-cyclodextrin alone and in combination with whey protein isolate (WPI) was used for nano-complex preparation. The WPI/CD-CNT nano-complex powder showed higher encapsulation efficiency (86.9%) and yield (70.5-80%) compared to CD-CNT powder. Both the spray-dried powders showed improved thermal stability, higher solubility (97%), less moisture content, and increased DPPH and ABTS radical scavenging activities indicating potential food and agricultural applications. In addition, the nano-complex powders showed a controlled release of core bio-actives under gastric and intestinal pH compared to the non-encapsulated CNT phenolic extract. Degradation kinetics studies of the CNT extract after thermal and light treatments were also discussed. Both the nano-complexes showed high stability under light and thermal treatment. The results suggest that valorization of CNT can be done through nano-complex preparation and WPI and ß-CD are efficient carrier materials for the encapsulation of polyphenols with potential applications in food and agriculture.

Development and validation of headspace Solid-Phase microextraction coupled with gas chromatography (HS-SPME-GC) method for the analysis of zingiber zerumbet L.

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography (GC-FID) was explored to determine the fingerprinting characteristic of Zingiber zerumbet L. volatiles to differentiate between different ginger species. The effect of different fibers [polydimethylsiloxane (PDMS, 7 µm), polyacrylate (PA, 85 µm)], different temperature and time on the HS-SPME-GC was investigated by using response surface methodology coupled with full factorial experimental design. The area percentage of the major sesquiterpenes (Zerumbone and α-humulene) were 56.3 ± 4.7% and 47.5 ± 27.2% with PA fiber, respectively at optimum condition of 70 °C and 30 min. Validation of the developed HS-SPME-GC method with limits of detection and quantification for zerumbone was 0.09 and 0.28 µg/g, respectively, demonstrating the suitable sensitivity of HS-SPME-GC method for the quantification of sesquiterpenes. Therefore, the simplicity of HS-SPME-GC makes it a convenient tool for qualitative and quantitative comparison of different ginger species targeting at the marker sesquiterpene molecule, zerumbone.

Effect of drying methods on the quality characteristics of dill (Anethum graveolens) greens.

Different drying methods hot air (HA), 50 °C, 58-63% relative humidity (RH); low humidity air (LHA), 50 °C and 28-30% RH; and radiofrequency (RF), 50 °C, 56-60% RH) were investigated for efficient dehydration of dill (Anethum graveolens) greens with optimal retention of color and constituents. The drying for HA and RF was marginally higher (∼ 22%) compared to HA. Lightness, greenness and yellowness of LHA dried sample were higher than those of the RF and hot-air dried dill greens. Aqueous methanolic extract of dill greens dehydrated by LHA method exhibited higher anti-oxidant activity. Forty-two compounds were identified representing ∼ 85% of the volatile oil and the major volatile compounds for fresh and dried dill leaf oil were α-Phellandrene, α-cymene, α-pinene, Apiol, 1,6-Cyclodecodiene, and 1-methyl-5-methylene. Dehydrated dill greens with their constituent polyphenols, carotenoids, ascorbic acid and minerals have been shown good consumer acceptance as well as shelf life and could serve as a valuable food additive to enhance human nutrition.