Effects of origin and harvest period on characterisation, structure and antioxidant activity of polysaccharides derived from Porphyra haitanensis

Abstract

In the present study, the influences of different origins and harvest periods on the characterisation, structure and antioxidant activity of Porphyra haitanensis polysaccharides (PHPs) were investigated. PHPR03 obtained from the third harvest period (late December) in Raoping possessed the highest content of sulphate group (14.70%), the lowest viscosity (434.34 mLÁg −1 ) and exhibited better antioxidant activity. FTIR spectrum confirmed that PHPs obtained in different origins and harvest periods had similar functional groups (O-H, C-H and C-O group). Thermal gravimetric analysis suggested that PHPR03 has good thermal stability until 182 °C. PHPR03 microstructure was detected using scanning electron microscopy, and it was mainly irregular flocs. Atomic force microscope data showed that its diameter and height ranged from 1.32 to 1.99 μm and 14.16 to 34.92 nm, respectively. X-ray diffraction and Congo red experiments indicated that PHPR03 belongs to amorphous material with weak rigidity and exists in the form of random coils in an aqueous solution. PHPR03 resulted in a decrease of thiobarbituric acidreactive substances value of ground pork. This study provides the theoretical basis for rational utilisation and further applications in the food industry of PHPs.

Recent progress in Porphyra haitanensis polysaccharides: Extraction, purification, structural insights, and their impact on gastrointestinal health and oxidative stress management

“…In this technique, specific proteolytic enzymes like proteases, pepsin, and papain are employed to target and break down proteins while preserving PHP's structural integrity ( Hong, Fan, Chalamaiah, & Wu, 2019 ). For instance, a solution containing 600 U/mL of alkaline protease was introduced to the mixture and incubated at 50 °C for 3 h to facilitate deproteinization ( Ji et al, 2022 ). Alternatively, papain (at a concentration of 0.1%, w / v ) was applied to cleave the protein components within the polysaccharide-protein mixture, resulting in protein-free PHP ( Wu et al, 2020 ).…”

“…For example, Wang et al employed an Ultrahyrogel™100 high-performance size exclusion column to determine three polysaccharide fractions, PHP-1, PHP-2, and PHP-3, using a series of standard calibration curve methods. Their findings showed molecular weights of 567.05 kDa, 414.09 kDa, and 323.80 kDa, respectively ( Ji et al, 2022 ). Additionally, Gong et al utilized a TSK-GEL G3000PWXL column to determine various PHP products (PHPD-I–IV), resulting in molecular weights of 329 kDa, 203 kDa, 128 kDa, and 10 kDa, respectively.…”

A novel antioxidant protein of non‐phycobiliprotein family derived from marine red alga Porphyra haitanensis

“…To our knowledge, most of the natural antioxidant substances obtained from plants are non‐toxic and safe for humans. Furthermore, many plants have medicinal properties in addition to being food 6,12‐14 …”

“…Furthermore, many plants have medicinal properties in addition to being food. 6,[12][13][14] Marine algae have been explored as potential sources of bioactive natural substances for decades, especially in the search for antioxidant ingredients. 6,12,15 Polysaccharides derived from marine algae are widely studied for their antioxidant properties; however, due to their complexity of structure, poor water solubility and low bioavailability, searching for other antioxidant components has been one of the main areas of research in food science and technology.…”

Effect of the harvest period on the structure and anti-allergic activity of Porphyra haitanensis polysaccharides

“…Theoretically, the harvest periods will influence the anti-allergic activity of PHPs, and understanding the relationship between harvest period and activity can facilitate the efficient application of PHPs in relevant functional foods and drugs; however, investigations on the polysaccharides from P. haitanensis in different harvest periods are limited currently. 19 Consequently, this study aimed to characterize the polysaccharides from P. haitanensis in different harvest periods and elucidate the anti-allergic activity and underlying mechanisms in an OVA-triggered food allergy mouse model. Our results provided a new direction for the efficient use of seaweed as functional food and revealed its potential use in controlling food allergies.…”