4th EucheMs chemistry congress

Poster Session 2
s1161
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - food chemistry
P - 0 5 9 8
Ph effeCtS on the PhytoCheMiCAL
CoMPoSition And AntioxidAnt ACtivity of
ProCeSSed PeACh
M. CoeLho 1 , A. oLiveirA 1 , h. GoMeS 1 ,
e. ALexAndre 1 , d. P. f. ALMeidA 2, 3 , M. PintAdo 1
1 CBQF, Escola Superior de Biotecnologia, Rua Dr. António
Bernardino de Almeida, 4200-072 Porto, Portugal
2 Faculdade de Ciencias, Universidade do Porto, Rua do
Campo Alegre, 687, 4169-007, Porto, Portugal
3 Frulact, S.A., Rua do Outeiro, 589, 4475-150 Gemunde, Maia,
Portugal
Adjustment of pH is often made in processed fruit products
to assure food safety or the stability or functionality of ingredients
or additives (e.g. pectins or sorbate). The objective of the work
was to assess the effect of pH on relevant markers of functional
and nutritional properties (antioxidant activity, phenolics and
carotenoids) of processed peach puree. Clingstone peach [Prunus
persica (L.) Batsch ‘Catherine’] fruits were reduced to puree and
the pH adjusted to 2.5; 3.0; 3.5; 4.0 and 4.5 with citric acid and
sodium phosphate. Purees were then heated in water-bath at
90 ºC for 10 minutes and subsequently stored during 90 days at
4.5 ºC and at 23 ºC. Hydrophilic extracts were obtained with
80% methanol and carotenoids were extracted as described by
Lavelli et al. (2009). Total antioxidant activity was assessed by
the ABTS method, total phenolics by Folin Ciocalteu’s method,
and total carotenoids by spectrophotometery. Individual phenolics
and carotenoids were separated and indentified by HPLC-DAD.
After 90 days storage the total antioxidant activity, total phenolics
and total carotenoids decreased, by 45%, 30%, and 47%,
respectively (average of both temperatures). The decline was
faster at 23 ºC than at 4.5 ºC, but the rate was not affected by pH.
Levels of neochlorogenic and chlorogenic acid (7 and
11 µg/ g fw respectively) were lower at pH 4.0 or 4.5 than at lower
pH values. Zeaxanthin, β-cryptoxanthin and β-carotene levels
decreased more during storage at pH 2.5 and 4.5 (70%, 47%, and
45%, respectively), than at the intermediate pH values. In
conclusion, puree pH, in the range 2.5 to 4.5 does not affect the
overall antioxidant activity, but the kinetics of changes in the
extractability of chlorogenic and neochlorogenic acids and
zeaxanthin
references:
1. Lavelli V., Pompei C., Casadei M. A., (2009), “Quality of
nectarine and peach nectars as affected by lye-peeling and
storage”, Food Chemistry, 115: 1291–1298
Keywords: Antioxidant activity; Carotenoids; Peach
processing; Phenolics;
4 th EucheMs chemistry congress
P - 0 5 9 9
enCAPSuLAtion of querCetin with Protein
And Protein-SteAriC ACid Mixture CoAtinG
MAteriALS And deterMinAtion of totAL
AntioxidAnt CAPACity uSinG CuPrAC Method
J. hizAL 1 , S. deMirCi CeKiC 2 , o. i. SAhin 1 , r. APAK 2
1 Yalova University, Chemical and Process Eng., Yalova, Turkey
2 Istanbul University, Chemistry, Istanbul, Turkey
Microencapsulation method has been widely used in food
industry in recent years. Retarding degradation of food additives,
it causes expanded shelf life and controlled releasing of core
materials through gastrointestinal system. Coating of surface takes
place via secondary interaction between internal and external
phase. Frequently encountered coating materials are cellulose
derivatives, starch derivatives, and algynates etc. Coating
antioxidant core with protein causes enhancing antioxidant
efficient. Proteins have two important roles: They reduce surface
tension at interface during emulsification and form
macromolecular layer. Gelatin is a protein used widely in
encapsulation process because of its excellent film-forming
properties.
At the first step in this study, quercetin was used as internal
phase and gelatin was used as external phase. After wall and core
material was reacted each other at fixed wall/core ratio, formed
microcapsules were powdered using freeze dryer. The minimum
mixing time and optimal wall/core ratio was found as 4 h and 1:1
respectively. At the second step, gelatin and stearic acid mixture
will be used as external phase.
After DSC analysis and cold-stage microscopy
determination and particle size measurement, surface
characterization of microcapsules will be achieved. And also,
encapsulation efficient and shelf life analyses and invitro digestion
experiments in synthetic saliva, stomach, and intestine liquids will
be performed. Antioxidant capacity will be quantitatively
determined using CUPRAC method in all experiments. In this
way, optimal wall matrix, wall/core phase ratio and shelf life will
be designated for microcapsules which core retention is
accomplished without reducing in their total antioxidant capacity.
Keywords: antioxidants; polymers; UV/Vis spectroscopy;
Analytical methods;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc