The objective of this study was to investigate the optimal condition for extracting dragon fruit peel (DFP) pectin with the best physicochemical properties and high antioxidant activity by using conventional extraction (CE) and ultrasound-assisted extraction (UAE). DFP was extracted using CE and UAE method at 45, 60 and 75°C for 30 and 60 min. In this study, UAE significantly improved antioxidant activity of the extracted DFP pectin when comparing to CE. DFP extracted with UAE at 45°C for 30 min had the highest antioxidant activity (51.58 ± 0.30 by DPPH, 39.81 ± 1.43 mgGAE/100 g by ABTS) (p < 0.05). Moreover, UAE also increased the production yield of sample at 45°C for 30 min (9.38 ± 0.50%) (p < 0.05) which was higher than the treatments with CE. The chemical properties of DFP pectin including equivalent weight, degree of esterification, methoxyl content and total anhydroronic acid revealed that DFP pectin could be categorized as low-methoxyl pectin. Present study demonstrated that DFP pectin was an ideal alternative source of pectin with high antioxidant activity compared with commercial citrus pectin. The optimal condition for extraction of pectin by UAE was at 45°C for 30 min which could be established as a potential method to extract pectin from DFP for industrial scale.

Collagen is an abundant structural protein found in many organs of animals, for example skin, bones, and connective tissues. Chicken trachea is a collagen-rich fraction of chicken offal that is converted to a solid waste stream during poultry processing. Collagen hydrolysates and peptides have unique biological properties, which is potentially converted from chicken trachea and can be used as a useful functional ingredient. Fresh chicken trachea was sterilized by autoclaving at 121°C for 30 min and dried using freeze drier to obtain chicken trachea flakes (CTF). CTF had 68.56% protein with the 50% solubility at pH 6–10. The enzymatic hydrolysis of chicken trachea was performed using Alcalase®, Flavourzyme®, Protamex®, and Papain under the optimal condition of each enzyme. An improvement in solubility was observed. Chicken trachea hydrolysates (CTH) with the highest solubility were detected in samples hydrolyzed with Alcalase®, follow by Protamex®, Papain, and Flavourzyme®, respectively. Within an hour of hydrolysis, the CTH obtained from Alcalase® hydrolysis had the highest total amino acid contents. The top three amino acids found in this hydrolyzate powder were Glutamic acid (Glu), Glycine (Gly), and Aspartic acid (Asp). Moreover, this sample exhibited the greatest antioxidant and bioactive properties as shown by the highest antioxidant capacity from DPPH and FRAP assay (4.42 TEAC µMol/mg CTH and 22.48 TEAC µMol/mg CTH, respectively) and the lowest IC₅₀ of ACE I inhibitor (0.41 mg/mL). These results suggested that Alcalase® hydrolysis provided the chicken trachea collagen hydrolyzate with unique properties that could be used in various food systems. GRAPHICAL ABSTRACT

The total phenolic content and antioxidant activities of the organic spent coffee ground obtained from different brewing methods were investigated. Among various brewing methods, the organic spent coffee ground showed the highest total phenolic content (TPC) and antioxidant activities and was selected as raw material for extracting phytochemicals using ultrasound assisted extraction (UAE) with different temperature, time, and solvent ratios. In terms of extraction time, the TPC and antioxidant activities were continuously increased until the extraction time reached to 40 min and then dramatically decreased indicating the appropriate extraction time. The extract with highest TPC (78.85 mg garlic acid equivalent/ml antioxidant crude extracts) and antioxidant activities was obtained when extracted with UAE at 50 °C, solvent ratios of 1:20 g/ml and 40 min. The assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ATBS) and ferric reducing antioxidant power (FRAP) were detected at 717.11 µM Trolox/antioxidant crude extracts, 711.23 µM Trolox/antioxidant crude extracts, and 2401.90 µM Ammonium ferrous sulfate/antioxidant crude extracts, respectively. When applied the antioxidant crude extracts from organic cold brew spent coffee ground into low fat pork sausage at 1.00%, the improvement of TPC and antioxidant activities was obtained. After storage for 14 days, the TPC and DPPH scavenging activity was increased to 18.07 mg garlic acid equivalent/100 g pork sausage and 159.76 µM Trolox/100 g pork sausage, respectively, while the 2‐thiobarbituric acid reactive substance values were reduced to 9.18 g malondialdehyde/100 g pork sausage. The rancidity of the sausage was ceased, and the shelf-life was prolonged when the extract was added. Graphical abstract

An ionic gelation technique based on an alginate-calcium-based encapsulation process was prepared as the delivery matrix for antioxidant crude extracts from cold brew spent coffee grounds (350 mg/mL). All the encapsulated samples were treated with different simulated food processes, namely pH 3, pH 7, low-temperature long-time (LTLT) pasteurization, and high-temperature short-time (HTST) pasteurization, to evaluate the stability of the encapsulated matrices. The results showed that alginate (2%, w/v)/maltodextrin (2%, w/v) (CM), and alginate (2%, w/v)/inulin (5%, w/v) (CI) could enhance encapsulation efficiency (89.76 and 85.78%, respectively) and provide lower swelling behavior after being treated using the simulated food processes. Both CM and CI could control the release of antioxidants during the gastric phase (2.28–3.98 and 2.52–4.00%, respectively) and gradual release in the intestinal phase (6.80–11.78 and 4.16–12.72%, respectively) compared to pure alginate (CA). In addition, pasteurization treatment at pH 7.0 produced the highest accumulated release of total phenolic content (TPC) and antioxidant activity (DPPH) after digestion in the in vitro gastrointestinal system compared to the other simulated food processes. The thermal process resulted in a greater release of compounds from the encapsulated matrix during the gastric phase. On the other hand, the treatment with pH 3.0 resulted in the lowest accumulated release of TPC and DPPH (5.08 and 5.12%, respectively), which indicated phytochemical protection.

White mugwort (Artemisia lactiflora Wall.), a traditional Chinese medicine, has been widely consumed in different forms for health care purposes. In this study, the in vitro digestion model of INFOGEST was used to investigate the bioaccessibility, stability, and antioxidant activity of polyphenols from two different forms of white mugwort, including dried powder (P 50, 100, and 150 mg/mL) and fresh extract (FE 5, 15, and 30 mg/mL). During digestion, the bioaccessibility of TPC and antioxidant activity were influenced by the form and ingested concentration of white mugwort. The highest bioaccessibility of the total phenolic content (TPC) and relative antioxidant activity were found at the lowest P and FE concentrations, as calculated relative to the TPC and antioxidant activity of P-MetOH and FE-MetOH based on the dry weight of the sample. Post-digestion, in comparison to P, FE had higher bioaccessibility (FE = 287.7% and P = 130.7%), relative DPPH radical scavenging activity (FE = 104.2% and P = 47.3%), and relative FRAP (FE = 673.5% and P = 66.5%). Nine compounds, 3-caffeoylquinic acid, 5-caffeoylquinic acid, 3,5-di-caffeoylquinic acid, sinapolymalate, isovitexin, kaempferol, morin, rutin, and quercetin, identified in both samples were modified during digestion, yet still provided strong antioxidant activity. These findings suggest that white mugwort extract possesses a higher polyphenol bioaccessibility, showing great potential as a functional ingredient.