Effect of drying method on functional properties and antioxidant activities of chicken skin gelatin hydrolysate

Abstract

The aim of this study is to investigate the functional and antioxidant properties of chicken skin gelatin hydrolysate (CSGH) as affected by the drying method used in the preparation of gelatin (freeze-dried and vacuum dried). CSGH obtained from freeze-dried gelatin showed better functional properties such as emulsifying activity index (EAI), water holding and oil binding capacity at different pH compared to CSGH produced from vacuum dried gelatin. Meanwhile, the CSGH of the vacuum dried gelatin exhibited a better emulsifying stability index (ESI), foaming capacity and stability. CSGH from freeze-dried gelatin showed better antioxidant, DPPH radical scavenging and metal chelating activity.

Effect of preparation method on physicochemical, scavenging, and proliferative properties of gelatin from Yak skin

“…OBC is highly related to the interaction between the components of oil and the texture of protein (Wan Omar & Sarbon, 2016). The OBC of the four samples was 16.14%, 17.27%, 20.18%, and 19.21% (Figure 2).…”

“…The gelatin prepared using the hot water extract method showed a higher WHC than that extracted using an enzyme ( p < .05). The WHC was considered to be related to the amount of hydrophilic amino acids (Cho et al., 2004; Rasli & Sarbon, 2015), and higher amounts of hydrophilic amino acid could increase the WHC of sample (Wan Omar & Sarbon, 2016). FEG had the lowest amount of hydrophilic amino acids in the four samples, such as Glu (6.06%), Arg (5.21%), His (0.71%), and Hyp (6.65%), which is may be the reason of the lowest WHC of FEG.…”

“…The WHC properties of the gelatin samples were analyzed by the method reported by Wan Omar and Sarbon (2016) with some modification. About 0.1 g of Yak skin gelatin was added into 10 ml of water and then kept for 45 min after being shaken at room temperature.…”

“…The FEG exhibited the lowest degree of MCA. The cause might be that FEG contained Lys (1.83%), His (0.71%), and Arg (5.21%), the amount of which was the minimum among the four samples (Wan Omar & Sarbon, 2016). Compared to the FEG from the freeze-dried enzymatic hydrolyzed gelatin, SDG from spray-dried hot-water-extracted gelatin had the highest degree of chelating activity, which may be because of its high carboxyl and amino groups and the highest amount of Lys (2.42%), His (0.65%), and Arg (5.57%); HCG had the second-highest degree of chelating activity maybe result from the amount of Lys (2.71%), His (0.47%), and Arg (5.44%); FDG was higher in MCA than FEG may be because of the high carboxyl and amino groups being highly exposed during the extract process.…”

“…Gelatin as a high molecular weight protein and has been extensively applied in diverse fields, such as food, cosmetics, pharmaceuticals, and photography, in which it acts as a thickener, stabilizer, or an ingredient (Haddar et al., 2012; Hamzeh, Benjakul, Sae‐leaw, & Sinthusamran, 2018; Wan Omar & Sarbon, 2016; Zhou & Regenstein, 2010). Because of this, the market's need for gelatin has experienced a noticeable increase.…”