Enzymatic Firming of Processed Red Pepper by Means of Exogenous Pectinesterase

Abstract

The objective of this investigation was to demonstrate that the firmness of a commercial vegetable product, diced and frozen red pepper (Capsicum annum var. Sendt), could be improved by the use of exogenous pectinesterase in an industrially relevant process. The diced pepper pieces 10 × 10 × 7 mm³ were infused under vacuum with a commercially available pectinesterase. The range of optimal process conditions was: 15–20°C, 45 min infusion time, a 10–25 mM CaCl₂ infusion brine, a w/w ratio of pepper fruit to infusion brine of 1.5:1, and an enzyme dosage of 30–60 pectinesterase units (PEU) per kg pepper fruit. The firmness as measured by back extrusion was improved by a factor of two to three. The effect of firming was robust and conserved after freezing and heating in a simulated household cooking process. The firming process seems easily adaptable to industrial conditions and may be applicable to other vegetable and fruit products.

Keywords:

• Enzyme
• Pectinesterase
• Firming
• Vegetables
• Fruit
• Vacuum infusion

Acknowledgments

Author Jensen expresses her sincere thanks to Gitte Budolfsen, M.Sc., Novozymes A/S, for her technical advice and general support during this work. She would also like to thank laboratory technician Helle Funck Petterson for practical help.