Release Characteristic and Antioxidant Activity of 4‐Hydroxybenzoic Acid (4HB) from Sodium Alginate and Polyvinyl Alcohol‐based Hydrogel

• Published in: ChemistrySelect (Weinheim) Vol. 7; no. 34
• Main Authors: Muangsri, Rapeepan, Chuysinuan, Piyachat, Thanyacharoen, Thanyaluck, Techasakul, Supanna, Sukhavattanakul, Pongpat, Ummartyotin, Sarute
• Format: Journal Article
• Language: English
• Published: 13.09.2022
• Subjects: 4-hydroxybenzoic acid (4HB); Antioxidant activity; Hydrogel; Sodium alginate
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202202329

1, 3 and 5 %wt of 4‐hydroxybenzoic acid (4HB) was successfully loaded into sodium alginate and polyvinyl alcohol‐based hydrogel composite for enhancement of antioxidant activities. Hydrogel was prepared by freeze thaw technique. No crosslinking agents were employed. Fourier transform infrared and X‐ray diffraction technique revealed that no significant change of functional group and crystallinity was observed when 4HB was loaded. By using freeze thaw technique, microstructural properties were well packed as reported by scanning electron microscope. Due to small amount of 4‐hydroxybenzoic acid, thermal characteristic was presented in the similar feature compare to pristine hydrogel. Differential scanning calorimetry exhibited that the glass transition and melting temperatures were reported to be 90 °C and 225 °C, respectively. However, tensile strength was slightly reduced by loading 4HB. The swelling behavior was very rapidly increased at the initial stage and then it was stable. Antioxidant activities were observed by means of DPPH assay. It was important to note that 4HB loaded into sodium alginate and polyvinyl alcohol‐based hydrogel exhibited outstanding properties to be candidate as food additives to help prevent food deterioration. 4‐Hydroxybenzoic Acid (4HB) was successfully loaded into sodium alginate and polyvinyl alcohol‐based hydrogel composite by the freeze thaw technique without crosslinking agents for enhancement of antioxidant activities.