Thermal treatment enhances the α-glucosidase inhibitory activity of bitter melon (Momordica charantia) by increasing the free form of phenolic compounds and the contents of Maillard reaction products

Evaluation of Antioxidant and Anti-Glycemic Characteristics of Aged Lemon Peel Induced by Three Thermal Browning Models: Hot-Air Drying, High Temperature and Humidity, and Steam-Drying Cycle

This study evaluated the antioxidant and anti-glycemic properties of black lemon Chenpi (BLC) (Citrus limon (L.) Burm. f. cv. Eureka), processed using three thermal browning models-hot-air drying (HAL), high temperature and humidity, and steam-drying cycle (SCL)-and compared them to fresh lemon peel and commercial Chenpi. The moisture-assisted aging technology (MAAT) is an environmentally friendly process for inducing browning reactions in the lemon peel, enhancing its functional properties. Our results demonstrated significant increases in sucrose, total flavonoid content, and antioxidant capacities (2,2-diphenylpicrylhydrazyl: 12.86 Trolox/g dry weight; ferric reducing antioxidant power: 14.92 mg Trolox/g dry weight) with the MAAT-HAL model. The MAAT-SCL model significantly improved the browning degree, fructose, total polyphenol content, narirutin, and 5-hydroxymethylfurfural synthesis (p < 0.05). Additionally, aged lemon peel exhibited potential α-glucosidase inhibitory activity (28.28%), suggesting its role in blood sugar regulation after meals. The multivariate analysis (principal component and heatmap analyses) indicated that BLC processed using the MAAT-SCL model exhibited similarities to commercial Chenpi, indicating its potential for functional food development. Our results indicate that MAAT-SCL can enhance the economic value of lemon by-products, offering a sustainable and functional alternative to traditional Chenpi.

Phytochemical, spectroscopic analysis and antifungal activity on bell peppers of hydrothermal bioactive metabolites of Humulus lupulus L. extracts

This study aimed to evaluate the impact of temperature on the potential extraction of bioactive compounds from aqueous hop extract samples. The main bioactive components were characterised and analysed by LC-MS/MS, FT-IR, phenolic compounds and total flavonoids. Antifungal activity was evaluated in vitro and in vivo in bell peppers. LC-MS/MS analysis demonstrated increases and decreases of bioactive compounds in both extracts depending on the extraction temperature of 25 or 65 °C. The bioactive compounds showed significant changes in the bands between 2786 to 3600 cm-1 and 1022 to 1729 cm-1 in the FT-IR spectrum. The highest antifungal activity against the microorganisms was observed in the EkuanotMT extract at an extraction temperature of 65 °C. The in vivo test with bell peppers presented antifungal activity during five days of evaluation under normal environmental conditions without refrigeration, presenting ≤ 52% of the disease due to F. oxysporum and A. solani.

The Browning Properties, Antioxidant Activity, and α-Glucosidase Inhibitory Improvement of Aged Oranges (Citrus sinensis)

Oranges contain many natural active chemicals, organic acids, and polysaccharides. Aging processing is commonly used to modify the color, quality, functional components, and stability of fruits. This study assesses the preparation of aging black oranges using various pre-treatments and solid fermentation. Oranges were aged for six weeks in fresh, non-blanching, blanching, and hot air-assisted aging cycle (AA) groups. The oranges' shrinkage ratio, color difference values, and soluble solids content changed significantly (p < 0.05). Principal component analysis indicated that aging fermentation treatment accelerated glycolysis and increased the ratio of reducing sugars. The enhanced browning can be associated with the oxidation of ascorbic acid (0.66-0.47 mg/g) and the formation of 5-hydroxymethylfurfural (5-HMF) (0.09 mg/g). Furthermore, the presence of free polyphenols led to an increase in the total polyphenol and total flavonoid content. It also had a synergistic effect with 5-HMF in increasing the 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging capacity and ferric ion-reducing antioxidant power (p < 0.05). AA had superior α-glucosidase inhibitory ability increasing from 67.31 to 80.48%. It also reduced the development time by 33%. Therefore, aging technology can enhance the bioactive compounds in oranges and provide a reference for future whole-fruit aging fermentation and health product creation.

Evaluate the effect of β-cyclodextrin on the sensory and physicochemical properties of bitter gourd extract during thermal processing

This study aims to evaluate the impact of β-cyclodextrin (β-CD) on the properties of the bitter gourd extract (BGE) under various heating conditions. In this work, the BGE and BGE supplemented with β-CD (0.75%) were heated at 60, 90, and 121 °C for 20 min before measuring the changes of bitterness, total saponin, polyphenol, antioxidant capacity, free amino acid, 5-hydroxymethylfurfural, browning intensity, and pH. It was found that β-CD mitigated the effect of heat treatment on the BGE, especially on saponins and color. Results also showed the debittering ability of β-CD was still preserved after heating duration. The bitter-masking and defensive mechanism of β-CD was also demonstrated using FTIR, thermogravimetric analysis, and molecular docking stimulation. These findings illustrated the addition of β-CD improved the thermal stability of the BGE, opening up the opportunities to incorporate BGE, which is promising in diabetes treatment but thermolabile, into heat-processed products.

The In Vitro Inhibitory Activity of Pacaya Palm Rachis versus Dipeptidyl Peptidase-IV, Angiotensin-Converting Enzyme, α-Glucosidase and α-Amylase

The pacaya palm (Chamaedorea tepejilote Liebm) is an important food that is commonly consumed in Mexico and Central America due to its nutritive value. It is also used as a nutraceutical food against some chronic diseases, such as hypertension and hyperglycemia. However, few reports have indicated its possible potential. For this reason, the goal of this research was to evaluate the effects of the enzymatic activity of the pacaya palm inflorescence rachis on both hypertension and hyperglycemia and the effects of thermal treatments on the enzymatic activity. The enzymatic inhibition of ACE (angiotensin-converting enzyme), DPP-IV (dipeptidyl peptidase-IV), α-glucosidase and α-amylase were evaluated, all with powder extracts of pacaya palm inflorescences rachis. The results indicated that thermally treated rachis showed increased enzymatic inhibitory activity against α-amylase and DPP-IV. However, all rachis, both with and without thermal treatment, showed low- or no enzymatic activity against α-glucosidase and ACE. Apparently, the mechanism of action of the antidiabetic effect of rachis is mediated by the inhibition of α-amylase and DPP-IV and does not contribute with a significant effect on enzymes involved in the hypertension mechanism. Finally, the properties of the extract were modified via the extraction method and the temperature tested.

Effects of Processing Conditions and Simulated Digestion In Vitro on the Antioxidant Activity, Inhibition of Xanthine Oxidase and Bioaccessibility of Epicatechin Gallate

The bioactivity and gastrointestinal stability of epicatechin gallate (ECG) may be affected by processing conditions. Results showed that the antioxidant ability and inhibitory activity on xanthine oxidase (XO) of ECG were higher at low pH values. Appropriate microwave and heating treatments improved the antioxidant (the scavenging rate increased from 71.75% to 92.71% and 80.88% under the microwave and heating treatments) and XO inhibitory activity (the inhibitory rate increased from 47.11% to 56.89% and 51.85% at the microwave and heating treatments) of ECG. The treated ECG led to a more compact structure of XO. Moreover, there may be synergistic antioxidant and inhibitory effects between ECG and its degradation products. The bioaccessibility of ECG after simulated digestion was untreated > microwave > heating, and the microwave-treated ECG still had good XO inhibitory activity after digestion. These findings may provide some significant information for the development of functional foods enriched in catechins.

Efficient thermal treatment of radish (Raphanus sativus) for enhancing its bioactive compounds

Old preserved radish (OPR), a traditional pickled-food of Asia, contains the healthy bioactive compounds, such as phenols and flavonoids. To preserve the phenols levels in radish by thermal treatment, which are decreased due to the polyphenol oxidase activity during long storage. Range of thermal processing evaluated to retain the maximum phenols level in the radish while processed at temperatures of 70 °C, 80 °C and 90 °C for 30 days. In this study, the bioactive compounds and antioxidant activity of thermal processing radish (TPR) were evaluated and compared with commercial products of OPR. Results showed the best condition of thermal processing, 80°C for 30 days, could increase the values of phenols, flavonoids and antioxidant activity that were 2.27, 2.74 and 2.89 times, respectively. When comparing the thermally processed radish or TPR with OPR, TPR has a higher content of phenols and flavonoids, indicating that the thermal processing was effective to increase the content of functional compounds in radish and significantly improved its nutritional values.

Accumulation of Antioxidative Phenolics and Carotenoids Using Thermal Processing in Different Stages of Momordica charantia Fruit

The bitter taste of M. charantia fruit limits its consumption, although the health benefits are well known. The thermal drying process is considered as an alternative method to reduce the bitterness. However, processing studies have rarely investigated physiochemical changes in fruit stages. The antioxidant activities and physiochemical properties of various fruit stages were investigated using different thermal treatments. The color of the thermally treated fruit varied depending on the temperature. When heat-treated for 3 days, the samples from the 30 °C and 90 °C treatments turned brown, while the color of the 60 °C sample did not change significantly. The antioxidant activities were increased in the thermally processed samples in a temperature-dependent manner, with an increase in phenolic compounds. In the 90 °C samples, the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity presented a 6.8-fold higher level than that of nonthermal treatment in mature yellow fruit (S3), whereas the activity showed about a 3.1-fold higher level in immature green (S1) and mature green (S2) fruits. Regardless of the stages, the carotenoid content tended to decrease with increasing temperature. In terms of antioxidant activities, these results suggested that mature yellow fruit is better for consumption using thermal processing.

A Novel Method for Quality Evaluation of Gardeniae fructus Praeparatus during Heat Processing Based on Sensory Characteristics and Chemical Compositions

The intrinsic chemical components and sensory characteristics of Gardeniae fructus Praeparatus (GFP) directly reflect its quality and subsequently, affect its clinical curative effect. However, there is little research on the correlation between the appearance traits and chemical compositions of GFP during heat processing. In this study, the major components of five typical processed decoction pieces of GFP were determined. With the deepening of processing, the contents of geniposidic acid and 5-HMF gradually increased, while the contents of deacetyl-asperulosidic acid methyl ester, gardenoside, and two pigments declined. Moreover, the electronic eye, electronic tongue, and electronic nose were applied to quantify GFP’s sensory properties. It was found that the chroma values showed a downward trend during the processing of GFP. The results of odor showed that ammonia, alkenes, hydrogen, and aromatic compounds were the material base for aroma characteristics. Complex bitterness in GF was more obvious than that in other GFP processed products. Furthermore, one mathematical model was established to evaluate the correlation between the sensory characteristics and chemical composition of GFP during five different stages. A cluster analysis and neural network analysis contributed to recognizing the processing stage of GFP. This study provided an alternative method for the exterior and interior correlation-based quality evaluation of herbs.