Roasting enhances sensory quality of wild almonds (
Amygdalus scoparia
). The aim of the study was to evaluate the use of microwaves (480 W for 3 or 4 min) in roasting of wild almonds in comparison ...with traditional Spanish (165 °C for 20 min) and Iranian (soaking in 20 % NaCl in water for 30 min, drying at 60 °C for 2 h and roasting at 135 °C for 20 min) hot-air processes. The influence of roasting wild almonds on moisture and oil contents, crispness, fatty acid profile, volatile compounds, and odour intensity was investigated. Roasting causes changes in appearance, texture and flavour, due to dehydration, browning, lipid oxidation, and diverse structural changes. The moisture content and hardness of the samples significantly decreased with all roasting methods. Roasting resulted in higher amounts of characteristics aroma compounds and only microwave roasting increased the oil content. The final recommendation is that microwave roasting at 480 W for 4 min led to roasted almonds of high physicochemical dark and intense colour (
L
*44.9,
a
*8.4, and
b
*19.6), the highest content of total volatile compounds (132 mg kg
−1
), 85.2 % of unsaturated fatty acids, and sensory (high intensity of “roasted almond” aroma) quality. Microwaves can be used for roasting wild almond as a quick, safe, and economical method.
•Effect of different dying methods on key quality parameters of dried jujube fruits.•Bioactive compounds, antioxidant capacity, and sensory attributes form quality.•The best quality of the dried ...product was found in fruits treated by FD and VMD 480–120W.
The aim of this study was to determine the effect of different dying methods, such as convective drying (CD: 50, 60, 70°C), vacuum-microwave drying (VMD: 120, 480, 480–120W), a combination of convective pre-drying and vacuum-microwave finish drying (CPD (60°C)-VMFD (480–120W), and freeze-drying (FD) on key quality parameters of dried jujube fruits (cv. “GAL”, “MSI”, and “PSI”). The parameters studied included bioactive compounds (flavan-3-ols and flavonols, identified by LC-PDA-MS, and vitamin C), antioxidant capacity (ABTS and FRAP), and sensory attributes (e.g. hardness, jujube-ID, and sweetness). The best quality of the dried product (high contents of bioactive compounds and high intensity of key sensory attributes) was found in fruits treated by FD and VMD 480–120W. The best cultivars were “PSI” and “GAL” from the point of view of bioactive content and sensory quality, respectively.
•Ziziphus jujube is a promising new crop well adapted to European weather conditions.•Nutrition component and antioxidant capacity in Ziziphus jujube was examined.•Fruits of cultivars ‘PSI’ and ‘MSI’ ...contained significantly more antioxidants than those of ‘GAL’ and ‘DAT’ cvs.•Jujube fruits showed strong nutritional and phytochemical potential to improve human health.
The interest in Ziziphus jujube is growing because it is an excellent source of nutrients and phytochemicals, and can contribute to a healthy diet. Nutritional compounds (phenolic compounds and l-ascorbic acid), and antioxidant capacity of 4 Spanish jujube cultivars were studied. Polyphenols were identified by LC–MS–QTof and quantified by UPLC–PDA–FL. A total of 25 polyphenolic compounds were identified and classified as 10 flavan-3-ols, 13 flavonols, 1 flavanone, and 1 dihydrochalcone. The content of total polyphenols (TP) ranged from 1442 to 3432mg/100g dry matter (dm) in fruits of the cultivars ‘DAT’ and ‘PSI’, respectively. Flavan-3-ols, the major group of polyphenols in jujube represented ∼92% of the TP content, whereas flavonols only amounted for about ∼8% each. The content of l-ascorbic acid was very high and took values in the range of 387–555mg/100g fresh weight (fw). Some Spanish jujube cultivars, especially ‘PSI’ and ‘MSI’, may be selected to promote the growth of cultivars with valuable nutritional and phytochemical beneficial effects on human health.
Drying is known as the best method to preserve fruits, vegetables, and herbs, decreasing not only the raw material volume but also its weight. This results in cheaper transportation and increments ...the product shelf life, limiting the food waste. Drying involves the application of energy in order to vaporize and mobilize the moisture content within the porous products. During this process, the heat and mass transfer occurs simultaneously. The quality of dehydrated fruits, vegetables, and aromatic herbs is a key problem closely related to the development and optimization of novel drying techniques. This review reports the weaknesses of common drying methods applied for fruits, vegetables, and aromatic herbs and the possible options to improve the quality of dried products using different drying techniques or their combination. The quality parameters under study include color, bulk density, porosity, shrinkage, phytochemicals, antioxidant capacity, sugars, proteins, volatile compounds, and sensory attributes. In general, drying leads to reduction in all studied parameters. However, the behavior of each plant material is different. On the whole, the optimal drying technique is different for each of the materials studied and specific conditions must be recommended after a proper evaluation of the drying protocols. However, a novel or combined technique must assure a high quality of dried products. Furthermore, the term quality must englobe the energy efficiency and the environmental impact leading to production of sustainable dried products.
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