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In this study, Panax notoginseng polysaccharides (PNPS) were extracted using ultrasonic/microwave-assisted extraction (UMAE). Based on single-factor experiments, ultrasonic duration, ultrasonic power, microwave duration, and microwave power were optimized using the response surface methodology (RSM). The results indicated that the optimal extraction parameters were an ultrasonic duration of 10 min, ultrasonic power of 50 W, microwave duration of 4 min, and microwave power of 540 W, which resulted in the highest extraction rate of PNPS at 11.03 ± 0.16%. Scanning electron microscopy images indicated that PNPS exhibited a porous and rough structure. The chemical structure of PNPS was analyzed using Fourier transform infrared spectroscopy and ultraviolet–visible spectroscopy. The molecular weight of PNPS was measured to be 4.148 × 105 Da; moreover, PNPS was found to be composed of glucose, galactose, galacturonic acid, arabinose, glucuronic acid, rhamnose, mannose, and ribose. The DPPH scavenging efficiency of PNPS (5 mg/mL) was evaluated to be 65.74%. Upon in vitro simulated saliva–gastrointestinal digestion, partly digested PNPS was obtained. In addition, differential scanning calorimetry (DSC) analysis and rheological testing results indicated that PNPS exhibited high thermal stability and favorable rheological properties. Therefore, PNPS extracted using UMAE exhibited broad application prospects for functional foods and pharmaceuticals.

Gelatin is an important biopolymer that is extracted from collagen and is extensively used in the food industry because of its excellent functional properties. However, native gelatin films are moisture-sensitive and readily dissolve, swell, or split when they come in contact with water, which limits its use in food packaging. Various natural and synthetic materials are incorporated in gelatin films to improve their mechanical and thermal stability, elasticity, flexibility, and oxygen and light barrier properties. This review discusses various methods used for gelatin-based film production and modification approaches for improving their functional properties, including mechanical strength, thermal stability, water and light barrier ability, solubility and swelling, and antimicrobial properties. Moreover, gelatin-based films extend the shelf life of stored products due to their antioxidant and anti-microbial properties. The potential applications, challenges, and limitations of gelatin-based films in food packaging are also discussed. However, further research is required to prolong the modification of gelatin-based films using naturally available edible materials that are not commercially utilized. Further, studies about possible health hazards associated with the continuous use of gelatin-based packaging films should also be conducted in the future.