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Food Chemistry 2018 Journal of Food, Nutrition and Population Health
ISSN: 2577-0586 Page 64
July 23-24, 2018
Rome, Italy
3rd Edition of International Conference on
Agriculture &
Food Chemistry
The compounds oxidation found in food, as in the case of
lipids, decreases the nutritional value and affects the products
organoleptic characteristics. Phenolic compounds are a good
option to prevent this negative effect. High temperatures usually
causes loss of phenolics compounds, while the mechanical effect
of extrusion is helpful for releasing bound phenolics from the
food matrix and induced antioxidant activities. On the other hand,
the high content of fiber in the shell of walnuts can be useful as
prebiotic or as a filter compound in the industry. Different extrusion
temperatures (33.25, 40, 70, 100 and 106.75ºC) and different
screw speeds (88.75, 100, 150, 200 and 211 rpm) were analyzed
using response surface methodology (RSM) to investigate
changes in dietary fiber (soluble and insoluble) contents, oil and
water absorption, water solubility, phytochemical contents and
antioxidant activity of extrusion products of walnut shell. The
results showed that the total dietary fiber extraction was increased,
in the best conditions, around 6%. The extrusion process no
affected the insoluble and soluble fraction. With 70ºC and 150 rpm,
the total phenolic content (TPC) reached their peak and increased
when compared with the control test. Antioxidant activity occurred
at higher levels in the range from 70ºC to 100ºC and 150 to 200
rpm. In colour, the three parameters measured, L* (lightness), a*
(greenness-redness), and b* (blueness-yellowness); these were
significantly affected (p<0.05) by the process temperature and
screw speed. Water and oil absorption capacity increased with the
extrusion process. These results demonstrated the potential that
the shell walnut extrusion has for the creation of new functional
products for animals and preservative in the food industry.
Biography
María Pilar Almajano has completed her PhD in Organic Chemistry in the CSIC
and postdoctoral studies in Reading University (UK). She has been working on
the topic of natural antioxidants for more than 15 years. She has around 60 sci-
entific publications in international journals. Since 2007 she is working at the
School of Engineering in the UPC, teaching Chemistry and Food Technology.
Juliana Villasante is a PhD student in natural antioxidants. She has completed
his degree in Engineering in Food Indsutry by “Instituto Tecnológico y de Es-
tudios Superiores de Monterrey” and master in Food Research, Development
and Innovation by Universidad de Barcelona. She has worked in the depart-
ments of Development and Innovation in different food industries.
Evaluation of extrusion effects on antioxidant activity and
total phenolics compounds in the shell walnut
Juliana Villasante Dueñas and María Pilar Almajano Pablos
Polytechnic University of Catalonia, Spain
Juliana Villasante Dueñas et al., J Food Nutr Popul Health 2018, Volume 2
DOI: 10.21767/2577-0586-C2-006