Font Size: a A A

Preparation Of Quinoa Antioxidant Peptide And Development Of Almond Compound Beverage

Posted on:2024-08-20Degree:MasterType:Thesis
Country:ChinaCandidate:Q DuFull Text:PDF
GTID:2531307166469054Subject:Agriculture
Abstract/Summary:PDF Full Text Request
Quinoa protein peptide is the product of quinoa protein hydrolysis.As a bioactive peptide,research in recent years has focused on the medical field,resulting in a single form of quinoa protein peptide products and results,which has not been fully developed and utilized.Using quinoa protein peptide to develop a beverage with primary health care effect has far-reaching significance in economic and social benefits.In this study,the local quinoa in Zhangjiakou was used as the experimental material,and the protein in white,red and black quinoa was extracted by alkali-soluble acid precipitation method.By comparing the effects of bromelain,papain,acid protease,neutral protease,alkaline protease,trypsin,complex protease and flavor protease on the antioxidant activity and hydrolysis degree of hydrolysates after enzymatic hydrolysis of three colors quinoa proteins,the antioxidant peptides prepared by alkaline protease enzymatic hydrolysis of black quinoa protein were screened by DPPH free radical scavenging rate and hydrolysis degree.The optimal hydrolysate was obtained by single factor test and response surface test to optimize the enzymatic hydrolysis conditions.The optimal process parameters for preparing antioxidant peptides by alkaline protease enzymatic hydrolysis of black quinoa protein were as follows:enzyme dosage was 4000 U·g-1.The hydrolysis time was 3.5 h,the hydrolysis temperature was 42°C,and the hydrolysis pH was 7.6.The antioxidant peptides of quinoa protein purified by Sephadex G-15 gel filtration chromatography showed three elution peaks of G-1,G-2and G-3.The antioxidant activity was determined by DPPH free radical scavenging rate.The antioxidant activity of G-1 component was the highest,which was(81.74±2.24)%.The peak eluent was collected and freeze-dried.The peptides were determined by liquid chromatography-mass spectrometry(LC-MS/MS),and the amino acid sequence of the peptides was determined by De novo sequencing.A total of 3393 peptides with a molecular weight of≤1500 were obtained.Among the peptides with a confidence level of more than 90%,the amino acid sequences were ASVGFKA,LLKAL,KMTTVH,TSPVHYE,and FDFHEK containing the reported antioxidant peptide fragments of KA,VH,and HE with good free radical scavenging rate.In addition,the peptides in this range contain hydrophobic amino acids and have certain antioxidant capacity.The extracted quinoa protein antioxidant peptide was applied to the compound beverage.Taking Zhangjiakou characteristic agricultural product almond as raw material,considering the color of the product,ascorbic acid,L-cysteine,sodium sulfite and phytic acid were added to protect the color of almond juice before beating.Taking the browning inhibition rate as the index,the single factor test and orthogonal test were carried out respectively.The best combination of composite color protection agent was 0.30%ascorbic acid,0.04%L-cysteine,0.03%sodium sulfite and 0.02%phytic acid.With sensory evaluation as the index,the single factor and orthogonal experiments were carried out on the different addition amounts of quinoa antioxidant peptide,almond juice,citric acid and white granulated sugar.The optimum technological conditions for quinoa almond antioxidant peptide beverage were 3%quinoa antioxidant peptide,30%almond juice,0.10%citric acid and 6%white granulated sugar.The antioxidant activity of the beverage was 35.65%higher than that of the beverage without quinoa antioxidant peptide.In order to ensure the stability of the beverage,the application effect of the compound stabilizer in the beverage was further studied.Single factor test and orthogonal test were carried out on different concentration gradients of xanthan gum,sodium hydroxymethyl cellulose and monoglyceride with centrifugal sedimentation rate as the index.The optimal combination of composite stabilizer was 0.06%xanthan gum,0.08%carboxymethyl cellulose and 0.04%monoglyceride.Through the above research,the best enzymes and process parameters for hydrolyzing black quinoa protein were obtained.After purification,peptides with antioxidant activity were obtained.The beverage produced by compounding with almond raw materials was milky white,with delicate and smooth taste,moderate viscosity,good fluidity,no precipitation and stratification,pure odor,special aroma of almond and quinoa,and certain antioxidant activity.The research results have certain guiding significance for broadening the utilization of quinoa and almonds,developing new food resources and developing new food products.
Keywords/Search Tags:Quinoa protein, Antioxidant activity, Peptide, Protease, Almonds, Beverages
PDF Full Text Request
Related items