Effects of different drying methods on phenolic substances and antioxidant activities of seedless raisins

Raisin Production by Convective-Microwave Dryer and Optimization of Ochratoxin A Content, Physicochemical, Sensory Characteristics, and Fungal Load of Raisin

Raisins are so popular in the human diet as a nutritional and sweet snack. The quality of this foodstuff depends on drying conditions. To minimize ochratoxin A (OTA) content and yeast and mold content (YMC) in raisins with favorable physicochemical and sensory properties, the response surface methodology (RSM) and the face-centered central composite design (FCCD) were utilized. The independent variables were studied over a range of microwave power (0-220 W) and temperature air (35°C-55°C). The microwave power had a significant effect on the OTA value and YMC of dried samples. The use of microwaves in drying contributed to a higher decline in OTA content and YMC than in conventionally dried samples. The regression models detected for OTA content, acidity, pH, rehydration ratio (RR), water holding capacity (WHC), shrinkage, appearance, texture, acceptability, and YMC were significant and reliable. The desirability function was applied to recognize an optimized situation. The result of the RSM analysis showed the optimum conditions for obtaining healthy raisins with desired physicochemical and sensory attributes by microwave-convective dryer at 220 W microwave power and 38.68°C air temperature.

Changes in Phenolic Composition and Bioactivities of Ayocote Beans under Boiling (Phaseolus coccineus L.)

Ayocote beans (Phaseolus coccineus L.) are a rich source of some bioactive molecules, such as phenolic compounds that exhibit antioxidant capacity that promote health benefits. Ayocote is mainly consumed after cooking, which can impact the antioxidant characteristics of the phenolic compounds responsible for some of its health benefits. Therefore, this study investigated the effects of boiling on the phenolic composition and bioactivities of ayocote beans before and after boiling. Boiling decreased the total phenolic content (70.2, 60.3, and 58.2%), total anthocyanin (74.3, 80.6, and 85.7%), and antioxidant activity (DPPH: 41.2, 46.9, and 59.1%; ORAC: 48.23, 53.6 and 65.7%) of brown, black, and purple ayocote beans, respectively. All the extracts also inhibited the activity of α-glucosidase with efficacy values from 29.7 to 87.6% and α-amylase from 25.31 to 56.2%, with moderate antiglycation potential (15.2 to 73.2%). Phenolic acids, anthocyanins, and flavonoid decreases were detected in boiled samples by HPLC-MS analysis. Although boiling reduced the phenolic compounds, bioactive compounds remained in a considerable content in boiled ayocote.

Analysis of trace elements in processed products of grapes and potential health risk assessment

Raisins and grape pekmez are consumed commonly by human all over the globe. Consumption of contaminated foods may be the likely pathway of heavy metal exposure. Therefore, the objectives of the present research were to quantify trace elements concentration in raisins and grape pekmez produced from locally grown grapes in Gonabad and to assess non-carcinogenic (HQ and HI) and carcinogenic (total cancer risk, CRt) health risks caused by trace elements exposure via oral intake of these products for children, teenagers, and adults. For this purpose, a totally 30 (15 raisins and 15 grape pekmez) samples were purchased from the vineyard gardeners and examined for ten trace elements including As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. The HI values signaled that the studied population consuming these products is at risk. The HQ, HI, and CRt values of the elements were in order of children > teenagers > adults. The highest cancer risk contribution was attributed to As and Ni for all the studied age groups in both raisins and grape pekmez samples. However, it is recommended that the concentration of trace elements in the soil and crops of the study area and its related health risks be regularly monitored to avoid significant health risks in the future.

Comparative elucidation of bioactive and volatile components in dry mature jujube fruit (Ziziphus jujuba Mill.) subjected to different drying methods

This study investigated the effects of convective drying(CD) and freeze drying(FD) on bioactive and volatile components in jujube. No significant difference in total phenolic, total flavonoids and antioxidant capacity among CD60, CD70, CD80 and FD samples (P > 0.05). LC-MS/MS analysis showed that this trend mainly originated from the dynamic equilibrium relationships between caffeic acid, chlorogenic acid, p-hydroxybenzoic acid, rutin, epicatechin, and quercetin. HS-SPME-GC-MS identified 31 volatile organic compounds (VOCs) comprising more than 80% aldehydes and acids. Principal component analysis distinguished the VOC characteristics of samples subjected to different drying methods. Six VOCs had an odor activity value (OAV) >1, most of which were fatty acid oxidation or Maillard reaction products. Combined with the precursor components, these reactions were speculated to be the major VOC-producing pathways in dried jujube. Considering the bioactive components and flavor retention, CD at 60 °C was an effective drying method with potential to replace FD.

The influence of varietal characteristics on the quality indicators of candied fruits from plum fruits

The influence of varietal characteristics of plum fruits on the physicochemical parameters of the drying process has been investigated. Revealed significant differences in the content of biologically active compounds on the example of varieties: Stanley, Big Stanley, Grossa di Felisio, President, Blue moon, August Delish, Kabardinskaya early. The consumption rates of raw materials for the production of candied fruits have been determined. The results of laboratory studies on the variation of the content of vitamins (C, P), anthocyanins in plum fruits, taking into account varietal characteristics, are presented. The drying process on a dryer with infrared rays led to a slight decrease in polyphenolic and mineral substances, and higher losses of vitamins in the finished candied fruit. The mathematical processing of the experimental data was carried out by the method of analysis of variance and descriptive statistics using the Microsoft Excel software package. In the production of candied plum fruits, optimal technological modes have been selected that contribute to a high yield of high-quality finished products, taking into account the varietal characteristics of the feedstock. According to biochemical and organoleptic indicators of the quality of candied fruits, Stanley and President varieties were distinguished, the energy value of which is 147.0 kcal with an organoleptic assessment of 4.9 points. The results of experimental biochemical and technological analyzes of fruits at individual technological stages of production made it possible to assess the intensity of complex processes that cause a qualitative transformation of raw materials.

LC-Q-Orbitrap-MS/MS Characterization, Antioxidant Activity, and α-Glucosidase-Inhibiting Activity With In Silico Analysis of Extract From Clausena Indica (Datz.) Oliv Fruit Pericarps

Clausena indica (Datz.) Oliv fruit pericarps (CIOPs) is an important agro-industrial by-product rich in active components. In this article, the effects of traditional and green deep eutectic solvents (DESs) on the high-performance liquid chromatography (HPLC) characterization, antioxidant activities, and α-glucosidase-inhibitory activity of phenolic extracts from CIOPs were investigated for the first time. The results showed that ChCl-Gly and Bet-CA had higher extraction efficiency for the total phenolic content (TPC, 64.14-64.83 mg GAE/g DW) and total flavonoid content (TFC, 47.83-48.11 mg RE/g DW) compared with the traditional solvents (water, methanol, and ethyl acetate). LC-Q-Orbitrap-MS/MS was adopted to identify the phenolic compositions of the CIOPs extracts. HPLC-diode array detection (HPLC-DAD) results indicated that arbutin, (-)-epigallocatechin, chlorogenic acid, procyanidin B1, (+)-catechin, and (-)-epicatechin were the major components for all extracts, especially for deep eutectic solvents (DESs). In addition, ChCl-Xyl and ChCl-Gly extracts showed higher antioxidant activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS+•), ferric reducing antioxidant power (FRAP), reducing power (RP), and cupric ion reducing antioxidant capacity (CUPRAC) than extracts extracted by other solvents. A strong α-glucosidase-inhibiting activity (IC50, 156.25-291.11 μg/ml) was found in three DESs extracts. Furthermore, in silico analysis of the major phenolics in the CIOPs extracts was carried out to explore their interactions with α-glucosidase. Multivariate analysis was carried out to determine the key factors affecting the antioxidant activity and α-glucosidase-inhibiting activity. In short, DES can be taken as a promising solvent for valorization and recovery of bioactive compounds from agro-industrial by-products. The results verified that CIOPs can be used as a prospective source rich in bio-active compounds applied in the food and pharmacy industries.