High-intensity pulsed electric fields or thermal treatment of broccoli juice: the effects of processing on minerals and free amino acids

Green tea is an unfermented tea containing a higher quantity of bioactive components. It has received a great deal of attention due to many biological activities, such as antioxidative, anticarcinogenic and antitumour activities. However, deterioration in quality after heating processes, in particular sterilization, was technical barrier for commercial ready-to-drink green tea production. It has already been demonstrated that pulsed electric fields (PEF) processing can alternatively be applied to deliver safe and shelf-stable products. In this paper the effect of conventional heat treatment (121 oC, 3min) and PEF treatment on the bioactive components (polyphenols, catechins and free amino acids) and color of green tea infusions was studied. There was a significant (P<0.05) decline in polyphenols, total catechins and total free amino acids induced by heat treatment, and the green tea infusions darkened and became less green and deeper yellow after the heating. Compared to heat processing, PEF can efficiently retain the bioactive components and original color of green tea infusions.

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Impact of High-Intensity Pulsed Electric Fields or Thermal Treatment on the Quality Attributes of Date Juice through Storage

Journal of Food Processing and Preservation ◽

10.1111/jfpp.13052 ◽

2016 ◽

Vol 41 (4) ◽

pp. e13052 ◽

Cited By ~ 14

Author(s):

H. Mtaoua ◽

R. Sánchez-Vega ◽

A. Ferchichi ◽

O. Martín-Belloso

Keyword(s):

Thermal Treatment ◽

Electric Fields ◽

High Intensity ◽

Pulsed Electric Fields ◽

Quality Attributes ◽

Date Juice

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Thermal Treatment Effect on Free Amino Acids in Honey Samples

Jurnal Teknologi ◽

10.11113/jt.v69.3169 ◽

2014 ◽

Vol 69 (4) ◽

Author(s):

Nur Ardawati Adnan ◽

Lee Suan Chua ◽

Mohamad Roji Sarmidi

Keyword(s):

Amino Acids ◽

Thermal Treatment ◽

Free Amino Acids ◽

Free Amino ◽

Botanical Origin ◽

Proteolytic Digestion ◽

Acacia Honey ◽

Lysine Concentration ◽

Before And After

Free amino acids are minor constituents in honey which are responsible for the determination of botanical origin of honey. However, the composition of free amino acids was likely to be altered upon thermal treatment. Therefore, this study was conducted to investigate the profile of free amino acids before and after thermal treatment at 90°C for 30 minutes. This study revealed that phenylalanine (101.84-139.74 mg/kg), tyrosine (28.71-138.36 mg/kg) and proline (23.93-83.21 mg/kg) were found abundantly in all honey samples such as Tualang, Gelam and Acacia honey samples. After the honey were heated, it was found that proline and threonine were significantly reduced, while tyrosine, valine and lysine were increased in all honey samples. The proteolytic digestion was responsible for the increase of tyrosine, valine and lysine concentration after thermal treatment. The decrease could be attributed to the denaturation of proline and threonine themselves, apart from the reaction between the carbonyl group of reducing sugar and the amino acids upon thermal treatment.

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