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.

The physicochemical properties and the release of sodium caseinate/ polysaccharide gum chlorophyll multiple-layer particles by rotary side-spray fluid bed technology.

Multiple-layer coating technology has widely applied to the quality modification of bioactive ingredients nowadays. This research used a rotary side-spray fluid bed to manufacture chlorophyll multiple-layer particles to adjust control release characteristics. The chlorophyll extracts were coated with sodium alginate (A1) and sodium caseinate (CA1) as the primary layer on sugar spheres and the product yield was 96.98 and 96.71%, respectively. The content of chlorophyll a and b (µg/g) were 41.04 and 13.20 in A1, 47.40 and 13.68 in CA1. The Fourier-transform infrared spectroscopy confirmed the bonding change and increase stability. The CA1 was coated with sodium alginate (CA-A), sodium carboxymethylcellulose (CA-C) and xanthan gum (CA-X) as the secondary layer, which can increase coated integrity, shell strength and thermal stability. The simulated gastrointestinal fluid showed 30.11% release in the stomach and 94.27% in the intestine, which improved release control characteristics. Increased retention rate and color stability in the storage test.

Effects of Roasting Sweet Potato (Ipomoea batatas L. Lam.): Quality, Volatile Compound Composition, and Sensory Evaluation.

Roasting can increase the Maillard reaction and caramelization of sweet potatoes to create an attractive appearance, color, aroma, and taste, and is rapidly increasing in the commercial market. This study mainly analyzed the influence of roasting sweet potatoes, with and without the peel, on sweet potato quality and flavor characteristics combined with sensory qualities. The results showed that the a* value (1.65-8.10), browning degree (58.30-108.91), total acidity (0.14-0.21 g/100 g, DW), and maltose content (0.00-46.16 g/100 g, DW) of roasted sweet potatoes increased with roasting time. A total of 46 volatile compounds were detected and 2-furanmethanol, furfural, and maltol were identified as the main sources of the aroma of roasted sweet potatoes. A sensory evaluation based on a comprehensive nine-point acceptance test and descriptive analysis showed that roasting for 1 to 2 h resulted in the highest acceptance score (6.20-6.65), including a golden-yellow color, sweet taste, and fibrous texture. The sweet potatoes became brown after roasting for 2.5 to 3 h and gained a burnt and sour taste, which reduced the acceptance score (4.65-5.75). These results can provide a reference for increased quality in the food industry production of roasted sweet potatoes.

Production and Physicochemical Properties of Starch Isolated from Djulis (Chenopodium formosanum).

Djulis (Chenopodium formosanum Koidz.) is an annual fast-growing underutilized pseudo cereal with a high percentage of starch content. In this study, djulis starch was extracted from the flour of dried grains by three different isolation procedures: (1) hydrochloric acid (HCl) isolation procedure (HP); (2) deionized water isolation procedure (WP); and (3) sodium hydroxide (NaOH) isolation procedure (NP), followed by investigation of the physicochemical properties of the isolated djulis starch. The amylose content of HP, WP, and NP was 22.14%, 24.15%, and 22.43%, respectively. For scanning electron microscopy (SEM) morphological observation, djulis starch presented a polygonal shape with granule sizes of 0.56-1.96, 0.74-3.02, and 0.62-2.48 µm, respectively. Djulis starch showed the classification of typical A-type x-ray patterns, and the relative degree of crystallinity for HP, WP, and NP was 33.15%, 36.17%, and 37.42%, respectively. Differential scanning calorimetry (DSC) analysis was used to determine the transition temperatures, transition range, and enthalpies of the gelatinization of starches. HP and WP isolated starch exhibited the highest ΔH 9.24 and 8.51 J/g, respectively, whereas NP starch showed the lowest ΔH of 6.95 J/g. The pasting temperatures of HP, WP, and NP isolated starch, which were analyzed by using a Rapid Visco Analyzer (RVA), were 71.70 °C, 72.80 °C, and 69.53 °C, respectively. The dependence of swelling power for the three isolated starches on temperature was tested at 10 °C with intervals between 60 °C and 90 °C. In short, the NP isolation procedure with a stable reaction is compelling from a technological point of view.

Stability and Quality of Anthocyanin in Purple Sweet Potato Extracts.

Because of the high nutritional value of anthocyanin in purple sweet potatoes (TN57), the stability and quality of anthocyanin in purple sweet potatoes during and after the processing were investigated in this study. First of all, the extraction methods with different parameters, such as temperature, time, solid-liquid ratio, pH value, and solvent were employed to get better extraction efficiencies. After that, DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azino-bis (3-ethylbenz thiazoline-6-sulphonic acid) were used to evaluate the anti-oxidation ability of the extracts. Lastly, the thermal degradation kinetics and photodegradation were used to obtain important degradation factors including the content of anthocyanin residue, degradation index (DI), color parameters, reaction rate (k), and chromatic aberration (ΔE). We found that the extraction condition as using 60% ethanol with 1% citric acid under 80 °C for 40 min was optimal for purple sweet potatoes, which obtained antioxidant capacity as 333 µM TE DPPH, 376 µM TE ABTS+, and 593.6 µM TE ferric ion reducing antioxidant power (FRAP). The results indicate that the most important parameter for the stability of anthocyanin in the purple sweet potato extract (PSPAE) was the pH value rather than temperature. In addition, there was no significant difference in chromatic aberration between the light and dark storage conditions under 37 °C. Thus, PSPAE has the potential to be developed as health foods and drinks rich in anthocyanin.

Preparation and Evaluation of Release Formulation of γ-Oryzanol/Algae Oil Self-Emulsified with Alginate Beads.

Self-emulsion improves solubility and bioavailability for γ-oryzanol/algae oil, and alginate beads can be used as controlled release carriers. In this study, self-emulsified alginate beads (SEABs) were prepared with different weight ratios of self-emulsion treatment (5%, 10%, 15%, 20%, and 30%) with alginate. We found that the microstructure with a surfactant of SEABs had a different appearance with alginate-based beads. The encapsulation of γ-oryzanol corresponded with the self-emulsion/alginate ratio, which was 98.93~60.20% with a different formulation of SEABs. During in vitro release, SEABs had the gastric protection of γ-oryzanol/algae oil, because γ-oryzanol and emulsion were not released in the simulated stomach fluid. When the SEABs were transferred to a simulation of the small intestine, they quickly began to swell and dissolve, releasing a higher content of the emulsion. We observed that the emulsion that formed had a bimodal distribution in the simulated intestinal fluid as a result of the hydrogel and emulsion droplets, leading to the formation of large aggregates. These results suggested that γ-oryzanol encapsulation within alginate beads via emulsification combined with gelation can serve as an effective controlled delivery system.

Effects of smoking process on the aroma characteristics and sensory qualities of dried longan.

In this study, the effects on the sensory quality and flavor profile of dried longan resulting from smoking it for 104 h were investigated. The results showed that, in terms of the quality of the dried longan. The smoking time influenced the fruit's water activity (0.70-0.92), soluble solids (30-60 。Brix), pH (6.13-6.71), and tendency to change from yellow to brown hues (ΔE: 3.13-12.83). We detected 42 volatile compound variations during smoking, of which 3-methyl-1-butanol, 3,7-dimethyl-1,3,6-octatriene, hydroxy butanone, and 1-octen-3-ol perceived aroma for longan. Aroma characteristics were evaluated smoky effect by agglomerative hierarchical cluster and principal component analysis. Forasmuch phenolic derivatives (smoky flavor) form lignin degradation correlated for the time, and organic compounds via oxidation (or hydrolyzation). We found get the smoky flavor and intermediate moisture of longan in smoked 72 h, which extended sensory and preservation that is beneficial to longan producers.

Roselle Anthocyanins: Antioxidant Properties and Stability to Heat and pH.

Roselle is rich in anthocyanins and is traditionally used to prepare a bright red beverage by decoction. However, heat treatment and different pH environments are often encountered during food processing, and these factors are often detrimental to anthocyanins. Therefore, it is very important to understand the influence of pH and heat treatment on anthocyanins for the application of roselle. This study determined the antioxidant properties of roselle extract, explored changes in the color and anthocyanin content in different pH environments, and evaluated the thermal stability of roselle anthocyanins using kinetic equations. The results showed that the roselle extract is rich in anthocyanins and has good antioxidant capacity (DPPH IC50 = 4.06 mg/mL, ABTS IC50 = 3.7 mg/mL). The anthocyanins themselves exhibited a certain degree of heat resistance and good color stability in an acidic environment. In contrast, they degraded very quickly and exhibited significant changes in color in a low-acid environment. The activation energy (Ea) ranges of the anthocyanins in the acidic and low-acid environments were quite different at 55.8⁻95.7 and 31.4⁻74.9 kJ/mol, respectively. Thus, it can be concluded that roselle anthocyanins are susceptible to heat treatment in a low-acid environment, affecting their quality and appearance; however, they can serve as a good source of functional ingredients and color in an acidic environment.

Variation Quality and Kinetic Parameter of Commercial n-3 PUFA-Rich Oil during Oxidation via Rancimat.

Different biological sources of n-3 polyunsaturated fatty acids (n-3 PUFA) in mainstream commercial products include algae and fish. Lipid oxidation in n-3 PUFA-rich oil is the most important cause of its deterioration. We investigated the kinetic parameters of n-3 PUFA-rich oil during oxidation via Rancimat (at a temperature range of 70~100 °C). This was done on the basis of the Arrhenius equation, which indicates that the activation energies (Ea) for oxidative stability are 82.84-96.98 KJ/mol. The chemical substrates of different oxidative levels resulting from oxidation via Rancimat at 80 °C were evaluated. At the initiation of oxidation, the tocopherols in the oil degraded very quickly, resulting in diminished protection against further oxidation. Then, the degradation of the fatty acids with n-3 PUFA-rich oil was evident because of decreased levels of PUFA along with increased levels of saturated fatty acids (SFA). The quality deterioration from n-3 PUFA-rich oil at the various oxidative levels was analyzed chemometrically. The anisidine value (p-AV, r: 0.92) and total oxidation value (TOTOX, r: 0.91) exhibited a good linear relationship in a principal component analysis (PCA), while oxidative change and a significant quality change to the induction period (IP) were detected through an agglomerative hierarchical cluster (AHC) analysis.

Characterization of Volatile Compounds with HS-SPME from Oxidized n-3 PUFA Rich Oils via Rancimat Tests.

Algae oil and fish oil are n-3 PUFA mainstream commercial products. The various sources for the stability of n-3 PUFA oxidation are influenced by the fatty acid composition, extraction and refined processing. In this study, the oil stability index (OSI) occurs within 2.3 to 7.6 hours with three different n-3 PUFA rich oil. To set the OSI in the Rancimat test as the oil stability limit and observed various degrees of oxidation (0, 25, 50, 75, 100 and 125%). The volatile oxidation compounds were analyzed via headspace-solid phase microextraction (HS-SPME) and GC/MS. We detected 51 volatile compound variations during the oxidation, which were composed of aldehydes, hydrocarbons, cyclic compounds, alcohols, benzene compounds, ketones, furans, ester and pyrrolidine. The off-flavor characteristics can be strongly influenced by the synergy effects of volatile oxidation compounds. Chemometric analysis (PCA and AHC) was applied to identify the sensitive oxidation marker compounds, which included a (E,E)-2,4-heptadienal appropriate marker, via lipid oxidation in the n-3 PUFA rich oil.

Distribution of phenolic compounds and antioxidative activities of rice kernel and their relationships with agronomic practice.

The phenolic and antioxidant activity of ethanolic extract of two Japonica rice cultivars, Taikeng no. 16 (medium and slender grain) and Kaohsiung no. 139 (short and round grain), grown under organic and conventional farming were examined. Analyses shows that Kaohsiung no. 139 contains the highest amount of secondary metabolites and continuous farming can increase its production. Results also suggest that phenolic content under different agronomic practices, has not shown significant differences but organically grown rice has proven to be better in higher accumulation of other secondary metabolites (2,2-diphenyl-1-picrylhydrazyl (DPPH), flavonoid content, and ferrous chelating capacity). In nutshell, genetic traits and environment have significant effect on phenolic compounds and the least variation reported under agronomic practices.

The role of polyphenol oxidase and peroxidase in the browning of water caltrop pericarp during heat treatment.

The mechanism of browning involving enzymatic browning was investigated in the pericarp of water caltrop, an Asian vegetable popular for its taste and medicinal properties. Polyphenol oxidase (PPO) and peroxidase (POD) activities were determined in pericarp at various times and temperatures. Water caltrop consisted of 44.22% moisture content, 37.23% crude fibre, and 2.63% crude protein. PPO and POD activities dropped from 62 and 38units/g sample, respectively, as water temperature was increased from 30 to 80°C. Optimum pH and temperature for PPO activity was at pH 5.0, 25-45°C, and POD activity peaked at 60°C. High PPO and POD activities at 40-50°C resulted in degradation of phenolic compounds, which led to increased aggregation of browning pigments and discolouration (lower L-values) of the pericarp. Enzymatic browning was determined as the major factor in the browning discolouration of heat-treated water caltrop pericarp.