Health-Promoting Properties of Processed Red Cabbage (Brassica oleracea var. capitata f. rubra): Effects of Drying Methods on Bio-Compound Retention.

The aim of this work is to describe the effect of convective drying (CD), vacuum drying (VD), infrared drying (IRD), low-temperature vacuum drying (LTVD) and freeze drying (FD) on bio-compound retention of red cabbage and its beneficial health properties. The total phenolics content (TPC), flavonoids (TFC), anthocyanin (TAC) and glucosinolates (TGC) were determined by spectrophotometry. The profiles of phenolic acids, amino acids and fatty acids were determined by HPLC-UV-DAD, LC-DAD and GC-FID, respectively. Antioxidant potential was verified by DPPH and ORAC assays. The antiproliferative activity was measured in the human gastric cell line (AGS). Anti-inflammatory activity was evaluated by phorbol 12-myristate 13-acetate and arachidonic acid models. VD showed high values of TPC = 11.89 ± 0.28 mg GAE/g d.m.; TFC = 11.30 ± 0.9 mg QE/g d.m.; TAC = 0.265 ± 0.01 mg Cya3glu/g d.m.; and TGC = 51.15 ± 3.31 µmol SE/g d.m. Caffeic acid, ferulic acid and sinapic acid were identified. The predominant amino acid and fatty acid were glutamic acid and γ-linolenic acid, respectively. The antioxidant potential was dependent on drying methods for both DPPH and ORAC assays. Dried red cabbage extracts showed clear anti-inflammatory and antiproliferative activity. The dehydration process is an alternative for the retention of bio-compounds and health-promoting properties of red cabbage.

Assessment of Bio-Compounds Content, Antioxidant Activity, and Neuroprotective Effect of Red Cabbage (Brassica oleracea var. Capitata rubra) Processed by Convective Drying at Different Temperatures.

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and no efficient therapy able to cure or slow down PD is available. In this study, dehydrated red cabbage was evaluated as a novel source of bio-compounds with neuroprotective capacity. Convective drying was carried out at different temperatures. Total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and glucosinolates (TGC) were determined using spectrophotometry, amino acid profile by LC-DAD and fatty acid profile by GC-FID. Phenolic characterization was determined by liquid chromatography-high-resolution mass spectrometry. Cytotoxicity and neuroprotection assays were evaluated in SH-SY5Y human cells, observing the effect on preformed fibrils of α-synuclein. Drying kinetic confirmed a shorter processing time with temperature increase. A high concentration of bio-compounds was observed, especially at 90 °C, with TPC = 1544.04 ± 11.4 mg GAE/100 g, TFC = 690.87 ± 4.0 mg QE/100 g and TGC = 5244.9 ± 260.2 µmol SngE/100 g. TAC degraded with temperature. Glutamic acid and arginine were predominant. Fatty acid profiles were relatively stable and were found to be mostly C18:3n3. The neochlorogenic acid was predominant. The extracts had no cytotoxicity and showed a neuroprotective effect at 24 h testing, which can extend in some cases to 48 h. The present findings underpin the use of red cabbage as a functional food ingredient.

Comprehensive Evaluation of the Bioactive Composition and Neuroprotective and Antimicrobial Properties of Vacuum-Dried Broccoli (Brassica oleracea var. italica) Powder and Its Antioxidants.

In this study, vacuum drying (VD) was employed as an approach to protect the bioactive components of and produce dried broccoli powders with a high biological activity. To achieve these goals, the effects of temperature (at the five levels of 50, 60, 70, 80 and 90 °C) and constant vacuum pressure (10 kPa) were evaluated. The results show that, with the increasing temperature, the drying time decreased. Based on the statistical tests, the Brunauer-Emmett-Teller (BET) model was found to fit well to sorption isotherms, whereas the Midilli and Kucuk model fit well to the drying kinetics. VD has a significant impact on several proximate composition values. As compared with the fresh sample, VD significantly reduced the total phenol, flavonoid and glucosinolate contents. However, it was shown that VD at higher temperatures (80 and 90 °C) contributed to a better antioxidant potential of broccoli powder. In contrast, 50 °C led to a better antimicrobial and neuroprotective effects, presumably due to the formation of isothiocyanate (ITC). Overall, this study demonstrates that VD is a promising technique for the development of extracts from broccoli powders that could be used as natural preservatives or as a neuroprotective agent.

Drying Kinetic Modeling and Assessment of Mineral Content, Antimicrobial Activity, and Potential α-Glucosidase Activity Inhibition of a Green Seaweed (Ulva spp.) Subjected to Different Drying Methods.

The green algal genus Ulva grows widely on all continents and is used for several applications such as functional foods, cosmeceuticals, nutraceuticals, and pharmaceuticals due to its nutritional characteristics. However, to increase its shelf-life and retain its bioactive components, it is necessary to apply some conservation technology, such as drying. The aim of this work is to describe the drying kinetic behavior of the green seaweed Ulva spp. by applying three dehydration methods: convective drying (CD), vacuum drying (VD), and solar drying (SD) by mathematical modeling and determining the retention of mineral content by atomic absorption spectroscopy and the antimicrobial potential against four strains such as Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae, and Penicillium sp. by measurement of inhibition zones and α-glucosidase activity inhibition, as reported by IC50 determination. A freeze-dried sample was used as the control. The equilibrium moisture values calculated using the Guggenheim-Anderson-de Boer model were 0.0108, 0.0108, and 0.0290 g water/g d.m., for CD, VD and SD, respectively. The Midilli and Kucuk model showed robustness to fit all the experimental data of drying kinetic modeling. Ulva spp. is an important source of potassium with a ratio of Na/K < 0.29. Inhibition halos were observed in all samples against S. cerevisiae and Penicillium sp. with higher values than fluconazole action. An inhibitory effect on α-glucosidase activity was observed in all samples, mainly in the freeze-dried sample. Finally, dried Ulva spp. is a rich source of macro- and microminerals with antimicrobial activity and is a potential α-glucosidase inhibitor. Thus, it can be considered as a potential functional ingredient for food manufacturing.

Dietary fibre in processed murta (Ugni molinae Turcz) berries: bioactive components and antioxidant capacity.

In this study the dietary fibre (DF) of fresh and processed murta berries was characterised with respect to bioactive and antioxidant properties. DF content was determined by three different methods (AOAC, dialysis membrane and indigestible fraction methods) comparing their effectiveness. The antioxidant activity of phenolic compounds (PC) in purée, fruit leather and isolated DF of murta berries was evaluated by DPPH and ORAC assays. Total phenolics and flavonoids linked to DF were determined by colorimetric tests, while PC profiles in the respective murta products were identified by HPLC. DF concentration was > 50 g/100 g dm, fluctuating between 52.03 ± 1.32 and 57.18 ± 0.61 g/100 g dm, exhibiting simultaneously high antioxidant activity, with ORAC values of 38,190 ± 661 and 26,425 ± 1399 µmol Trolox equivalent/100 g dm in the isolated DF of fresh murta berries and processed murta fruit leather respectively, which enabled a classification as antioxidant dietary fibre. Total phenolics and flavonoids linked to DF retained a high concentration in the fruit leather, implying a favourable effect of processing. Gallic acid and pyrogallol were found associated to DF, at a level of 34.03 ± 1.17 and 631.07 ± 22.10 mg/100 g dm in the fresh berries respectively, which conferred to murta berries a functional property not yet reported. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05416-1.