Search Results (39)

Blanching is a critical postharvest step that influences broccoli color, texture, flavor, and nutritional quality, and may affect the formation of warmed-over flavor (WOF) related volatile compounds under thermal processing. This study compares hot water blanching (HWB, 98 ± 1 °C, 30 to 150 s) and steam blanching (SB, 100 °C, 30 to 150 s) by analyzing color, texture, peroxidase activity, electronic nose, volatile compounds, sulforaphane content, and scanning electron microscopy (SEM) to determine how blanching conditions influence physicochemical attributes, cellular organization, and WOF-related volatile profiles in broccoli. Overall quality retention was superior with SB, particularly at 60 s, as evidenced by lower residual enzyme activity, improved firmness retention, better maintained cellular structure as observed microscopically, and higher sulforaphane retention relative to HWB. Multivariate analysis identified nine key volatile markers (variable importance in projection (VIP) > 1 and relative odor activity value (ROAV) > 1), including the WOF-associated aldehyde pentanal. Broccoli treated by SB for 60 s exhibited markedly lower levels of these aldehydes than samples subjected to HWB. Correlation analysis revealed a positive correlation between sulforaphane and sulfur-containing volatile compounds, including dimethyl disulfide and dimethyl trisulfide. This correlation mainly derived from the superimposed degradation of different precursor pools under thermal action: at high temperatures, dimethyl disulfide is one of the main volatile products generated from the thermal degradation of sulforaphane; meanwhile, during heating, intermediates derived from S-methyl-l-cysteine sulfoxide undergo thermal reactions to form dimethyl disulfide and dimethyl trisulfide. Collectively, these results support SB as an effective strategy to mitigate WOF while maintaining the nutritional quality of broccoli and potentially other cruciferous vegetables. Full article

Hot air drying of pumpkin (Cucurbita moschata) and its by-products, mainly the peel and placenta with seeds, has been investigated, analysing the influence of pretreatments on drying kinetics and bioactive compound content. Pumpkin flours not only stand out for their microbiological stability (low water activity), but also for their bioactive compounds important for health, including phenolic compounds and other antioxidants. Pretreatments prior to drying may improve both the quality and the drying efficiency, although their optimization has not been studied in pumpkin by-product flours. Hence, we studied different pretreatments, such as steam blanching (SB) and freezing (F) (−18 °C), to investigate their effect on the pumpkin by-product flour quality (color and water activity) after drying and compared to flours made with the edible part (pulp). In addition, different drying kinetics models were evaluated. SB pulp and peel achieved lower water activity (0.25/0.20) than F (0.35/0.36), compared to untreated pumpkin by-product flour (0.40/0.45). The SB placenta with seeds achieved a lower water activity (0.19) than F (0.55). The total phenolic content (TPC) increased up to 41.7, 60.2 and 40.9% in pre-treated and dried pulp, peel and placenta with seeds, respectively, compared to control (CTRL). A similar result was obtained for total flavonoid content (TFC), where increases of up to 86.4, 36.4, and 32.2% were observed in pre-treated pulp, peel and placenta with seeds, respectively. For total antioxidant capacity (TAC), results showed an increase of up to 33.1% in pre-treated peel, with slight reductions in pulp (20.1%) and placenta with seeds (39.1%), compared to CTRL. These results are promising for obtaining new dehydrated plant products from industrial processing by-products, while maintaining their beneficial health characteristics. These powdered products can be used in future research on the formulation of new fortified foods, such as bakery products, or the development of natural additives for beverages or soups. Full article

White radish is a nutritious root vegetable that provides dietary fiber, essential vitamins and minerals, and a range of bioactive compounds. This study aimed to determine how steam and microwave blanching, pulsed electric field, ultrasound, osmotic dehydration with inulin or trehalose, and coating with spices such as turmeric or sweet paprika influence the characteristics of convective infrared dried white radish slices. To assess the effect of each pretreatment, moisture content, water activity, shrinkage, density, texture, color parameters, structural characteristics (SEM and µ-CT), vapor adsorption, thermal changes, and antioxidant properties were analyzed. Osmotic dehydration with inulin most effectively limited shrinkage and color change, stabilized the microstructure, and resulted in the highest relative phenolic content and antioxidant activity (TPC, DPPH). Spice-coated samples showed low shrinkage, low hardness and breaking work, and vivid color. Furthermore, µ-CT microstructure analysis showed that these samples had the highest porosity, with those with paprika reaching 57.5%. In contrast, blanching, ultrasound, and PEF led to greater structural changes and increased hygroscopicity. Multivariate analyses confirmed the significant influence of the type of pre-treatment on the quality characteristics of the dried material. Osmotic dehydration and spice coating proved to be the most effective methods for obtaining structurally stable and visually attractive dried white radish slices with attractive bioactive compounds. Full article

Opportunities to capture anticipated niche markets for diverse populations continue to rise. Okra (Abelmoschus esculentus L.), considered a high-value crop, is rich in nutritional and medicinal properties; however, fresh okra is highly perishable. This study examined the effects of thermal pre-treatments and drying processes in combination on the nutritional quality of dried okra. The experiment consisted of two thermal treatments (steam-blanched and hot water-blanched, and the control) and three drying treatments (freeze-dried, hot air-dried, and infrared-dried). Okra was grown in black plastic mulch, harvested twice per week, and processed three times throughout the growing season. The study analyzed moisture content, water activity, phytonutrients, ascorbic acid, β-carotene, and antioxidant activities. No significant differences were observed in moisture content and water activity among the treatments. Significant differences were observed among treatments and harvest time for total phenolic and flavonoid contents and antioxidant activity. Notable differences in β-carotene content were observed across all treatments. Based on the findings, the steam-blanched freeze-dried treatment was the most effective preservation technique for maintaining the nutritional and functional quality of dried okra. Hot water-blanching, hot air-drying, and infrared-drying were the least effective for the development of a high-value, nutrient-dense dried okra value-added product. Full article

Mugwort (Artemisia princeps Pamp.) is a traditional herb widely used across East Asia; despite this, optimal processing methods to preserve its functional components and palatability have not been fully established. Thus, we aimed to, for the first time, systematically examine the effects of 16 processing methods that combine blanching (steaming or boiling), drying [freeze-drying (FD), mechanical drying, shade drying, or silica gel drying], and rolling on mugwort’s appearance, total polyphenol content (TPC), antioxidant activity, and sensory characteristics. Our results showed that steaming for ≥2 min followed by FD was the most effective method for maintaining a high TPC and a vibrant green color. In contrast, boiling with sodium bicarbonate preserved color but substantially reduced both TPC and chlorogenic acid (CGA) content compared with steaming. Sensory evaluation revealed that consumers consistently preferred steaming over other processing methods. Liquid chromatography–tandem mass spectrometry analysis revealed that prolonged drying induced CGA isomerization to neochlorogenic acid. Moreover, processing time substantially influenced CGA stability, while high TPC did not compromise mugwort flavor. Our findings imply that an optimized combination of steaming and FD maximizes both functional and sensory quality of mugwort, highlighting the potential of mugwort tea as a flavorful functional food. Full article

Thermal processing alters the nutritional and functional properties of vegetable food. In this study, using electrophoretic, spectrophotometric, and statistical analyses, we analyzed the effects of boiling, blanching, steaming, and blanching followed by pan-frying and air-frying on the concentration of bioactive compounds in kale and chard, and the biological effects of their extracts. In addition to analyzing the vegetable tissues, the residual water remaining after thermal processing was also examined to assess the nutritional potential of this often overlooked and typically discarded by-product. The residual cooking water had the highest antioxidant capacity, according to ABTS, DPPH, and FRAP assays (57.83% ± 18.16%, 33.58% ± 16.55%, and 81.58% ± 0.78% for kale and 74.53% ± 4.56%, 13.62% ± 7.34%, and 82.97% ± 0.44% for chard, respectively). Air-frying and cooking water contained the highest total phenolics (0.48 ± 0.17 mg GAE/g fw and 0.35 ± 0.06 mg GAE/g fw for kale and 0.88 ± 0.21 mg GAE/g fw and 0.80 ± 0.06 mg GAE/g fw for chard, respectively). Thermally processed chard had a higher concentration of oxidative marker H₂O₂ than kale. An inverse relationship between soluble sugars and H₂O₂ levels was observed. In kale, cooking processes caused the greatest reduction in soluble sugars, whereas in chard, this effect was most pronounced during blanching. Chard had more photosynthetic pigments than kale. Heat treatments caused more differences between kale samples than chard samples. Pan-frying best preserved chlorophylls, porphyrins, and carotenoids. According to both PC and HC analysis, the tissues of kale were clearly distinguishable from the water remaining after boiling/blanching/steaming kale. These results may help to optimize industrial processing conditions to better preserve bioactive compounds and create opportunities for the valorization of cooking by-products. Full article

Artichoke by-products are rich in bioactive compounds and could be valorized for use as flour. Blanching is a critical pretreatment in the production of flour from artichokes, as it helps preserve bioactive and nutritional compounds before cutting, drying and milling. However, studies on the blanching of artichoke by-products for flour production are scarce in contrast to those studies on edible artichoke parts. In this article, the effect of different blanching treatments (steam or immersion; 3–15 min) on the bioactive compounds (total phenolic content, TPC; total antioxidant capacity, TAC; and inulin) and color quality of flours of artichoke by-products (obtained after cutting, drying and milling of stems and bracts) was studied. Blanching treatments induced increases in TPC, TAC and inulin, although those increments varied greatly depending on the treatment type and artichoke part. In particular, steaming (15 min) induced the highest TPC increment in artichoke hearts and stems (94 and 46%, respectively); TAC increment in hearts, stems and bracts (987, 1107 and 1660%, respectively); and inulin increment in hearts and stems (106 and 14%, respectively). Steaming (3 min) induced the highest inulin increment in bracts (40%). Immersion (15 min) induced the highest TPC increment in bracts (632%). In addition, the short blanching treatment (3 min) was not enough to inactivate browning enzymes with browning index values of 75, 52 and 67, which were similar, or even higher, to control samples (unblanched). In conclusion, steam blanching for 15 and 3 min induced the highest bioactive contents in stems and hearts and inulin and TAC contents in bracts. Full article

Fixation is a necessary step in bamboo leaf powder processing and plays a decisive role in determining its color, aroma, and taste. It is irreplaceable for maintaining quality, stability, and forming unique sensory characteristics. In this study, optimal conditions for steamed bamboo leaf powder (SBL), baked bamboo leaf powder (BBL), and blanched bamboo leaf powder (BCBL) were determined by measuring chlorophyll content, color parameters, and enzyme inactivation. In addition, volatile organic compounds (VOCs) in bamboo leaf powder processed with different fixation methods were analyzed using gas chromatography–mass spectrometry (GC-MS), gas chromatography–olfactometry (GC-O), and relative odor activity value (ROAV). Steaming for 120 s, baking for 60 s, and blanching for 30 s effectively preserved color, with a* values of −1.37, −1.44, and −1.62, all superior to untreated bamboo leaf powder (UBL). Among them, BCBL showed the best color stability, with the lowest color difference (ΔE = 0.66) compared with fresh bamboo leaves (FBLs). Results showed that BBL retained the highest VOC abundance (15.67% of FBLs), followed by SBL (5.73%) and BCBL (5.48%). Hexanal, nonanal, linalool, and α-ionone were identified as key aroma contributors, forming green, fresh, and floral notes. Sensory differences were evident: SBL exhibited strong seaweed-like and roasted notes, BCBL showed partial loss of characteristic aromas, while BBL preserved grass, fruity, and woody attributes. These findings highlight the significant influence of fixation methods on aroma-active compounds and color stability, providing a theoretical basis for producing bamboo leaf powder with superior sensory quality. Full article

Vegetables are usually thermally processed before consumption to improve their flavor and safety. In this work, the effect of boiling (BO), blanching (BL), steaming (ST), air-frying (AF), and pan-frying (PF)on the nutritional value and bioactivity of broccoli (Brassica oleracea var. italica) heads was investigated, including a comparative analysis of the tissue and the cooking water remaining after the treatments. Using spectrophotometric methods, AF broccoli was found to have the highest levels (p ≤ 0.05) of hydroxycinnamic acids (1.58 ± 0.71 mg CAE/g fw), total glucosinolates (3.76 ± 2.09 mg SinE/g fw), carotenoids (6.73 ± 2.89 mg/kg fw), and lycopene (0.91 ± 0.19 mg/kg fw). Steamed and AF broccoli had the highest total phenolics (0.72 ± 0.12 mg GAE/g fw and 0.65 ± 0.15 mg GAE/g fw, respectively; p ≤ 0.05). ST broccoli also had the highest levels of soluble sugars (11.04 ± 2.45 mg SucE/g fw) and total tannins (0.46 ± 0.19 mg GAE/g fw). The water remaining after cooking broccoli (BOW) had the highest total flavonoids (2.72 ± 0.59 mg QE/g fw) and antioxidant capacity (ABTS and FRAP, 57.57 ± 18.22% and 79.34 ± 3.28%, respectively; p ≤ 0.05). The DPPH assay showed that AF (36.12 ± 15.71%) and ST (35.48 ± 2.28%) had the strongest antioxidant potential. DNA nicking assay showed that BOW and BLW were the most effective in preserving plasmid DNA supercoiled form (99.51% and 94.81%, respectively; p ≤ 0.05). These results demonstrate that thermal processing significantly affects the phytochemical composition and functional properties of broccoli, with steaming and air-frying generally preserving the highest nutritional quality. Additionally, cooking water, often discarded, retains high levels of bioactive compounds and exhibits strong antioxidant and DNA-protective effects. To the best of our knowledge, this is the first study to investigate how different thermal processing techniques of vegetables influence their ability to protect plasmid DNA structure. Furthermore, this is the first study to compare the DNA-protective effects of broccoli tissue extracts and the water remaining after cooking broccoli. Full article

American ginseng (AG) has long been used as an ingredient in the food and pharmaceutical industries because of its nutritional and economic value. AG is rich in nutrients, and its quality is greatly affected by how it is processed. However, there is a relative paucity of research on the comprehensive evaluation of different processing techniques of AG. This study evaluated the differences in quality formation and properties of low-temperature softened, blanched, steamed followed by hot air drying, and vacuum freeze-dried AG (LTS-HAD, BL-HAD, ST-HAD, and VFD, respectively). The results demonstrated that AGs treated with VFD had the fastest drying time (85 h) and succeeded in preserving the color and microstructure of fresh ginseng. The contents of ginsenoside Rg1 and Rb1 in LTS-HAD samples were 2.81 ± 0.01 mg/g and 10.68 ± 0.66 mg/g, respectively, which were significantly higher than those in VFD samples (p < 0.05). Moreover, ST-HAD samples had an attractive reddish-brown appearance and higher antioxidant activity. Simultaneously, the formation of the ginsenosides Rg6, (S) Rg3, (R) Rg3, Rk1, and Rg5 was discovered. BL-HAD samples had an intermediate quality among the above samples. A total of 58 volatile compounds were identified, including aldehydes (14), alcohols (13), ketones (10), esters (6), terpenes (6), acids (5), and heterocyclic compounds (4). PCA of ginsenosides and volatile components, as well as correlation analysis with color and antioxidant activity, resulted in the identification of different processed products and potential bioactive components. Full article

The subject of the research was a comparative analysis of the rehydration process of dried apples in cubic form. Cubes of dried Idared apples were subjected to various pre-treatment processes, including steam blanching, microwave heating and osmotic dehydration in a sucrose solution. The pre-treatment was followed by a convection drying process conducted using two different drying systems. The rehydration process was carried out at a water temperature of 20 °C for 150 min. Rehydration kinetics, instantaneous increments in rehydrate mass and the relative and absolute moisture content of rehydrated samples were analyzed based on the tests. The rehydration process rates were also determined. It was observed that osmotic drying in a 10% sucrose solution reduced the rehydration process of dried apples by up to 32%. Full article

In this study, we analyzed the effects of three pretreatment methods—microwave, steam, and blanching—on the quality of Honeysuckle to determine the optimal pretreatment method; we then investigated the influence of different drying temperatures, vacuum levels, and rotation speeds on the drying characteristics, color, and active ingredient content of the Honeysuckle that was pretreated by the optimal pretreatment method during rotary microwave vacuum drying. The results indicated that a microwave pretreatment for 75 s was the optimal pretreatment method, which enhanced the retention of active ingredients and effectively improved the browning of the material. During the process of rotary microwave vacuum drying, as the temperature increased, the vacuum level rose, and the rotation speed increased, the drying rate gradually increased. However, excessively high vacuum levels and rapid rotation speeds could actually decrease the drying rate. In addition, the total phenols, total flavonoids, antioxidant activity, and various active ingredients of Honeysuckle dried by rotary microwave vacuum were effectively preserved. Furthermore, its rehydration properties and color were significantly superior to those dried through sun drying. The TIOPSIS method analysis showed that the optimal process parameters were a temperature of 50 °C, a vacuum level of −0.070 MPa, and a rotation speed of 35 Hz, which exhibited the highest relative closeness (0.76). The comprehensive analysis indicated that microwave pretreatment followed by rotary microwave vacuum drying was a promising drying method with potential applications in the dehydration of agricultural products and medicinal plants. Full article

The present study investigated the changes in the organoleptic characteristics, nutraceuticals, and antioxidant activity of tomato fruits subjected to different thermal processes: tomato sauce (80 °C for 30 min), blanching treatment (100 °C for 10 s), and the superheated steam method (SHS; 100 °C for 7 min) compared with fresh tomato fruit. Even though SHS negatively modified the color of the product (L* −7% than fresh tomatoes), it was the only technology able to increase the antioxidant activity compared with fresh tomatoes (e.g., +40.3% in ABTS assay), whilst lycopene and ascorbic acid contents reported similar values to fresh tomatoes. Regarding lycopene, only 5Z-lycopene (with a higher bioavailability than (all-E)-isomers) was found in all samples, and SHS maintained the same level observed in fresh tomato fruit. Furthermore, SHS technology preserved the antioxidant effects of fresh tomato extract even in human endothelial cells. This result confirmed those obtained in previous “cell-free” assays and demonstrated that SHS treatment significantly maintains the biological properties of tomato fruit in preventing oxidative stress. However, heat-treated tomato extracts did not show the same effects as fresh tomato extract against noradrenaline-induced vasoconstriction in isolated rat aortic rings. This study demonstrates that the use of SHS technology can be considered an innovative and sustainable thermal process (in terms of maintaining the nutraceutical quality) for tomato fruits, thus paving the way for future investigations on the effects of fresh and heat-treated tomatoes after intestinal absorption in vitro and in vivo. Full article

Phospholipids (PLs) play a crucial role in the nutraceutical field due to their various health benefits, including supporting acetylcholine production, enhancing cell membrane fluidity, and promoting cognitive functions. This study aimed to investigate the PL composition of selected agri-foods, including grains, vegetables, and fruits, and assess the effects of cooking methods. The major PLs identified in most agri-foods were phosphatidylethanolamine (PE) and phosphatidylcholine (PC). Additionally, lyso-phosphatidylethanolamine and lyso-phosphatidylcholine were found in rice, grains, and wheat, while N-acyl-phosphatidylethanolamine was detected in grains, wheat, and some vegetables. Phosphatidylinositol was present in fruits and vegetables, and phosphatidylserine was exclusively found in mushrooms. The PL composition was influenced by cooking methods, with boiling, steaming, blanching, and roasting increasing the PL content, while salting tended to decrease it. Although most agri-foods contained higher levels of PC than PE, citrus fruits under long-term low-temperature storage had significantly more PE than PC. This study established a PL database for the selected agri- and processed/cooked foods, providing insights into changes in PL composition and content based on cooking methods. Given the important health functions of each PL, consuming various agri-foods and incorporating different cooking methods for optimal health benefits is advisable. Full article

This study aimed to improve apple slices’ color and drying kinetics by optimizing the hot-air drying process, utilizing machine and deep learning models. Different steam blanching times (30, 60, 90, and 120 s), drying temperatures (50, 55, 60, 65, and 70 °C), and humidity control methods (full humidity removal or temperature–humidity control) were examined. These factors significantly affected the quality of apple slices. 60 s blanching, 60 °C temperature, and full dehumidification represented the optimal drying conditions for apple slices’ dehydration, achieving better drying kinetics and the best color quality. However, the fastest drying process (40 min) was obtained at a 60 °C drying temperature combined with complete dehumidification after 90 s blanching. Furthermore, machine and deep learning models, including backpropagation (BP), convolutional neural network–long short-term memory (CNN-LSTM), temporal convolutional network (TCN), and long short-term memory (LSTM) networks, effectively predicted the moisture content and color variation in apple slices. Among these, LSTM networks demonstrated exceptional predictive performance with an R² value exceeding 0.98, indicating superior accuracy. This study provides a scientific foundation for optimizing the drying process of apple slices and illustrates the potential application of deep learning in the agricultural processing and engineering fields. Full article