Characterization and Preparation of Aspergillus niger Naringinase for Debittering Citrus Juice

• Published in: Journal of food science Vol. 77; no. 1; pp. C1 - C7
• Main Authors: Ni, Hui, Chen, Feng, Cai, Huinong, Xiao, Anfeng, You, Qi, Lu, Yunzhen
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.01.2012; Wiley; Wiley Subscription Services, Inc
• Subjects: Animals; Aspergillus niger; Aspergillus niger - enzymology; beta-Glucosidase - adverse effects; beta-Glucosidase - chemistry; beta-Glucosidase - isolation & purification; beta-Glucosidase - metabolism; Beverages - analysis; Biological and medical sciences; Citrus; Citrus - chemistry; citrus juice; debittering; Enzyme Stability; Enzymes; Female; Flavanones - metabolism; Flavoring Agents - adverse effects; Flavoring Agents - chemistry; Flavoring Agents - isolation & purification; Flavoring Agents - metabolism; Food industries; Food preservation; Food science; Freeze Drying; Fruit and vegetable industries; Fruit juices; Fundamental and applied biological sciences. Psychology; Fungal Proteins - adverse effects; Fungal Proteins - chemistry; Fungal Proteins - isolation & purification; Fungal Proteins - metabolism; Hydrogen-Ion Concentration; Male; Maximum Tolerated Dose; Mice; Mice, Inbred Strains; Molecular Weight; Multienzyme Complexes - adverse effects; Multienzyme Complexes - chemistry; Multienzyme Complexes - isolation & purification; Multienzyme Complexes - metabolism; naringinase; oral acute toxicity; Protein Subunits - adverse effects; Protein Subunits - chemistry; Protein Subunits - isolation & purification; Protein Subunits - metabolism; Taste; Temperature; Toxicity; Fruit; Toxicity; Acute; Rutaceae; debittering; Fungi; Characterization; Citrus; naringinase; Aspergillus niger; oral acute toxicity; Dicotyledones; Preparation; Angiospermae; Spermatophyta; Fungi Imperfecti; citrus juice
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1750-3841.2011.02471.x

:  Naringinase from Aspergillus niger was prepared and characterized to evaluate its effectiveness in debittering citrus juice. The enzyme was purified to homogeneity by sulfate fractionation and chromatographies on Q‐Sepharose, Sephacryl S‐200, and S‐100 HR columns, and estimated by gel filtration chromatography (GFC) to have a molecular weight (MW) of 131 kDa, of which its subunit was measured by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis to be around 65.5 kDa. The enzyme showed active and stable pH ranges both within 4.5 to 5.0. Its optimal temperature was in the range of 45 to 55 °C. Freeze drying provided an estimated enzymatic recovery of 95.9%, greater than spray drying with the recovery at 55.6%. The freeze‐drying powder could retain its enzymatic activity stably at 4 °C for 6 mo. Also, the enzyme in 0.220 U/mL citrus juice could sufficiently remove the naringin for the bitterness. Oral acute toxicity study revealed the maximum tolerated dose (MTD) of the naringinase powder was >10 g/kg in mice. The contents of arsenic (As), lead (Pb), mercury (Hg), the aerobic plate count, and coliform number in the enzyme powder all met the criteria for food use. These characteristics suggest that the naringinase from A. niger is efficient and suitable for debittering the citrus juice, and the process consisting of fermentation, salt precipitation, ion exchange, ultrafiltration, and freeze drying is a promising means to prepare the naringinase for food industry, setting up a strong base to enzymatically debitter citrus juice. Practical Application:  This study focused on characterization, preparation, and validation of naringinase from A. niger, which provided useful information on how to prepare, store, and use the naringinase. In addition, this naringinase met the safety standards for food use and showed strong ability to remove the bitter taste from citrus juice, which provided useful information for interested readers, and the food industry.