Search Results (9)

Dried lemon slices (LSs) have become increasingly popular as a healthful beverage when infused in hot water. This study examined the effects of freeze drying (FD), hot air drying (HAD), heat pump drying (HPD), and far-infrared drying (FID) on the quality of dried LSs and their brewed beverages. The results show that FD-LSs and their corresponding beverages have the most appealing appearance and maximum levels of ascorbic acid (2.47 and 0.80 mg/g, respectively), synephrine (8.15 and 0.94 mg/g, respectively), and the overwhelming majority of natural and available phenolic compounds, as well as the strongest antioxidant activity, although numerous volatile compounds in FD-LSs were in the lowest abundances. HPD-LSs exhibited similar trends to FD-LSs but contained the peak concentrations of limonene (2258.87 μg/g), γ-terpinene (704.19 μg/g), β-pinene (502.92 μg/g), and α-pinene (188.91 μg/g), which were the four most abundant volatile compounds in dried LSs. Additionally, active ingredients in HPD-LSs generally featured relative high levels of available amounts. In contrast, HAD- and FID-LSs typically displayed unfavorable coloration and low retention levels of natural and available active ingredients. Consequently, FD and HPD demonstrate superior suitability for the commercial-scale production of dried LSs. Full article

Beetroot peel, an underutilised by-product of the food industry, has significant potential for valorisation due to its high content of bioactive compounds and natural pigments. This study aimed to sustainably reintroduce beetroot peel into the food chain by enriching the nutritional value of dehydrated apple snacks. Five experimental formulations of apple slices were developed: dipped in 5% RBPP in water, dipped in 10% RBPP in water, dipped in 5% RBPP in 50% lemon juice, dipped in 10% RBPP in 50% lemon juice all seasoned with cinnamon powder, and a control formulation. The biochemical analysis showed that the total phenolic content (2780.01 ± 68.38 mg GAE/100 g DM) and antioxidant activity of apple snacks significantly increased (503.96 ± 1.83 µmol TE/g DM). Sensory evaluation indicated that snacks with beetroot peel powder and lemon juice achieved the highest scores in colour, flavour, and acceptability. These results demonstrate that the valorisation of beetroot peel has the potential to reduce agro-industrial waste and also enhance the nutritional and functional quality of apple snacks. It is recommended that beetroot peel be further explored as a cost-effective natural ingredient to develop healthier, value-added snack products within a circular economy framework. Full article

This study investigates the impact of various pre-drying treatments and drying methods on the physicochemical, phytochemical, and sensorial quality of dried bananas. To achieve this goal, four pretreatment solutions were used before drying to enhance the quality characteristics of banana slices: citric acid 1% and ascorbic acid 1%, sucrose 10%, sodium bisulphate 0.5%, and lemon juice 5% and acetic acid 0.5%. Two drying methods were applied, sun drying (SD) and tunnel drying (TD). The dried slices were evaluated for moisture, total acidity, water activity (a_w), browning index, rehydration ratio (RR), reducing sugar, ascorbic acid, total phenol, and DPPH %, as well as sensory attributes (color, odor, taste, texture, and overall acceptability). The results showed that the retention of acid content, ascorbic acid, total phenolics, and DPPH in slice samples dried in TD was higher than that in SD. The browning index values in the TD samples were lower than those in the SD samples. Moreover, the TD samples showed a higher RR than the SD samples. It is noted that the pretreatment solutions used have an important role in improving the final quality characteristics of dried banana slices. The results of the sensory evaluation revealed a significant difference in the degrees of color and texture for the slices pretreated with sodium bisulphate. Meanwhile, the rates of taste and odor were significantly higher for the sucrose-pretreated slices. TD can improve the drying kinetics, shorten the drying time, and maintain the quality of the dried slices. Full article

Acrylamide is classified as a toxic and a prospective carcinogen to humans, and it is formed during thermal process via Maillard reaction. In order to find innovative ways to diminish acrylamide formation in potato chips, several extracts of agricultural wastes including potato peels, olive leaves, lemon peels and pomegranate peels extracts were examined as a soaking pre-treatment before frying step. Total phenolic, total flavonoids, antioxidant activity, and the reduction in sugar and asparagine contents were additionally performed. Proximate composition of these wastes was found to be markedly higher in fat, carbohydrate and ash contents. Lemon peels and potato peels showed almost similar phenolic content (162 ± 0.93 and 157 ± 0.88 mg GAE /g, respectively) and exhibited strong ABTS and DPPH radical scavenging activities than the other wastes. The reduction percentage of reducing sugars and asparagine after soaking treatment ranged from 28.70 to 39.57% and from 22.71 to 29.55%, respectively. HPLC results showed higher level of acrylamide formation in control sample (104.94 mg/kg) and by using the wastes extracts of lemon peels, potato peels, olive leaves, and pomegranate peels succeeded to mitigate acrylamide level by 86.11%, 69.66%, 34.03%, and 11.08%, respectively. Thus, it can be concluded that the soaking of potato slices in the tested wastes extracts as antioxidant as pre-treatment before frying reduces the formation of acrylamide and in this way, the risks connected to acrylamide consumption could be regulated and managed. Full article

Apple fruits are high in phenolic compounds, sugar and dietary fiber content and are rich in malic acid and vitamins, with a significant impact on the organoleptic quality and its health-promoting properties. They can be turned out in value-added product such as apple chips due to the low cost of raw material. The aim of the study was to obtain apple chips, fat-free, healthy, traditionally dried and without added sugar, which can be easily obtained and capitalized economically, as well as the evaluation of their physico-chemical and sensory qualities. The apple chips were produced from three apple cultivars (‘Starkrimson’, ‘Golden Delicious’ and ‘Florina’) by drying the apple fruits in an oven and a dehydrator at 65 °C. To inactivate the browning enzymes, the apple slices were immersed in a solution of lemon salt (4%) for 7 min before drying. Apple chips were sensory-evaluated and relevant parameters were analyzed at defined intervals during storage at room temperature up to 21 days. The water activity (aw) values of apple chip samples dried in the oven ranged from 0.544 to 0.650, while for the samples dried in the dehydrator, aw values were between 0.374 and 0.426. During the storage, the pH of apple chips varied very little, while titratable acidity increased for all samples. Compared with fresh apple slices, it was observed that the total soluble solids (TSS) content of all dried apple chip samples decreased. Color parameters and browning and whitening indexes differed depending on the apple cultivars and dryer type used. Full article

In recent years, the market for minimally processed fruit has increased. Fresh-cut fruits are characterized by a short shelf life due to the processing phases that accelerate the ripening courses. The aim of this work is to analyze the effect on the quality of fresh-cut Hayward kiwis of three different edible coatings based on (1) Aloe vera gel, (2) Aloe vera gel + hydroxypropyl methylcellulose and (3) Aloe vera gel + lemon essential oil. Fruit firmness, weight loss, color, soluble solids content, titratable acidity, microbial load and sensory analysis were evaluated as fresh after 2, 4, 7 and 10 days. Aloe vera gel and Aloe vera gel + lemon essential oil maintained the best values, as they acted as a barrier to gas exchange and further reduced the microbial load. These results were confirmed by sensory analysis: Aloe vera gel + hydroxypropyl methylcellulose does not alter the natural taste of kiwi slices, Aloe vera gel + lemon essential oil gives the characteristic taste of lemon essential oil and Aloe vera gel gives an herbaceous taste. The Aloe vera gel, in combination with these additives, maintains the ability to preserve the quality of fresh-cut kiwifruit. Full article

Recently, there is increasing use of edible and biodegradable films and packaging that are both environmentally friendly and functional for storage and market distribution. Fresh-cut ‘Fuji’ apples, harvested in an organic farm, were treated, using a spraying technique, with three new edible coatings based on Aloe vera gel (AVG—40% v/w) and in combination with natural additives: lemon essential oil (LEO—1% v/w) and hydroxypropyl methylcellulose (HPMC—0.1% v/w) and compared with untreated sample (CTR), the physicochemical and sensory characteristics and the proximate compounds were evaluated. During cold storage, weight loss, soluble solids content, and color of uncoated slices were reduced, while softening, ripening, browning, and acidity were accelerated. In contrast, the AVG/HPMC treatment significantly delayed the above parameters related to post-harvest quality loss, while the AVG/LEO treatment delayed the browning processes, maintaining an excellent color during cold storage. Concerning proximate compounds, the treatments did not alter their concentration in the fruit tissues. Sensory analyses revealed no detrimental effect on taste, aroma, or flavor. Our data evidenced the positive effect of Aloe vera gel in combination with LEO and HPMC on fresh-cut apple quality as an innovative and sustainable technique to maintain fresh-cut apple quality. Full article

A new hybrid solar dryer was designed and constructed in this study, which consisted of a flat-plate solar collector with dual-function (DF-FPSC), drying chamber with glass, fan etc. The DF-FPSC was firstly applied in drying agricultural products. The innovative application of hybrid solar dryer can control the drying chamber air temperature within a suitable range by different operation strategies. Drying experiments for lemon slices in the hybrid solar dryer were conducted by comparing open sun drying (OSD). Eight mathematical models of drying characteristics were employed to select the most suitable model for describing the drying curves of lemon slices. Furthermore, energy, exergy economic and environment (4E) analysis were also adopted to analyze the drying process of lemon slices. The results show that under the same experimental condition, the drying capability of the hybrid solar dryer was stronger than that of OSD. Meanwhile, it was found that the Two term and Wang and Singh models were the most suitable for fitting the lemon slices’ drying characteristics inside the hybrid solar dryer. The drying chamber air temperature can be controlled under about 60 °C during the process of lemon slices’ drying. The experimental results show the feasibility and validity of the proposed hybrid solar dryer. Full article

Edible plant fruits are safe raw materials free of toxicants and rich in biomolecules for reducing metal ions and stabilizing nanoparticles. Zinc oxide nanoparticles (ZnONPs) and titanium dioxide nanoparticles (TiO₂NPs) are the most produced consumer nanomaterials and have known antibacterial activities but have rarely been used against phytopathogenic bacteria. Here, we synthesized ZnONPs and TiO₂NPs simply by mixing ZnO or TiO₂ solution with a lemon fruit extract at room temperature and showed their antibacterial activities against Dickeya dadantii, which causes sweet potato stem and root rot disease occurring in major sweet potato planting areas in China. Ultraviolet–visible spectrometry and energy dispersive spectroscopy determined their physiochemical characteristics. Transmission electron microscopy, scanning electron microscopy, and X-ray diffraction spectroscopy revealed the nanoscale size and polymorphic crystalline structures of the ZnONPs and TiO₂NPs. Fourier-transform infrared spectroscopy revealed their surface stabilization groups from the lemon fruit extract. In contrast to ZnO and TiO₂, which had no antibacterial activity against D. dadantii, ZnONPs and TiO₂NPs showed inhibitions on D. dadantii growth, swimming motility, biofilm formation, and maceration of sweet potato tuber slices. ZnONPs and TiO₂NPs showed similar extents of antibacterial activities, which increased with the increase of nanoparticle concentrations, and inhibited about 60% of D. dadantii activities at the concentration of 50 µg∙mL⁻¹. The green synthetic ZnONPs and TiO₂NPs can be used to control the sweet potato soft rot disease by control of pathogen contamination of seed tubers. Full article