Pickering emulsion stabilized by cellulose nanocrystals from ginkgo seed shells and preparation method thereof

A method for preparing a Pickering emulsion using cellulose from ginkgo seed shells, comprising the following steps:

• (1) purifying cellulose from ginkgo seed shells:
• mixing crushed ginkgo seed shells with a preheated 2-5 wt % sodium hydroxide solution in a material-liquid ratio of 1:20 to 1:40 (w/v);
• then heating the mixture in a water bath at 80-100° C. for 1-3 h;
• carrying out filtering and washing with deionized water 2-4 times;
• then carrying out drying with hot air at 40-60° C. to obtain a dried cellulose;
• mixing the dried cellulose with a rinsing solution in a material-liquid ratio of 1:20 to 1:50 (w/v);
• heating the mixture in a water bath at 80-100° C. for 1-3 h;
• then filtering the mixture to remove the rinsing solution;
• and carrying out drying with hot air at 40-60° C. to obtain dried cellulose powder;
• (2) preparing cellulose nanocrystals (CNCs):
• mixing the dried cellulose powder obtained in step (1) with a preheated sulfuric acid solution with a mass concentration of 58-64% for carrying out a hydrolysis reaction, wherein a hydrolysis temperature is 40-50° C., the hydrolysis reaction time is 10-60 min, and a material-liquid ratio of the cellulose to the sulfuric acid solution is 1:10 to 1:20 (w/v);
• after the hydrolysis, immediately terminating the hydrolysis reaction with 10-15 times of deionized water by volume;
• then carrying out centrifugation to remove a sulfuric acid hydrolysate;
• redispersing centrifuged precipitate into deionized water to obtain a suspension;
• filling a dialysis bag with the suspension;
• and repeating dialysis with deionized water until a pH value of the suspension is stable to obtain a cellulose microcrystal suspension;
• (3) preparing cellulose nanocrystals with different aspect ratios:
• homogenizing the cellulose suspension obtained in step (2), wherein a homogenization pressure is 10-100 MPa, the number of cycles is 4, and a homogenization temperature is room temperature;
• cellulose nanocrystals with high aspect ratios are obtained by homogenization treatment at a pressure of 10-30 MPa;
• and cellulose nanocrystals with low aspect ratios are obtained by homogenization treatment at a pressure of 30-100 MPa;
• and
• (4) preparing the Pickering emulsion:
• mixing the cellulose nanocrystals in step (3) used as a solid particle emulsifier with an oil phase, and carrying out emulsification to obtain the Pickering emulsion.