3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
P73 ANALyTICAL MEASuREMENTS AND
PhISICOChEMICAL PARAMETERS
DETERMINATION IN STRAwbERRIES AND
RASPbERRIES ENhANCE PRODuCTION
A. GAGO, F. MOREnO, T. GARCíA-BARRERA and
J. L. GóMEZ-ARIZA
Dpto. de Química y CC.MM, Facultad de Ciencias Experimentales,
Universidad de Huelva, Campus de El Carmen,
21007 Huelva, Spain,
amanda.gago@dqcm.uhu.es
Introduction
Strawberry is one of the most delicious fruits of the
world, which is a rich source of vitamins and minerals 1 .The
strawberry harvest in Huelva was included in the main group
of agricultural activities in which Spain have an important
position in the framework of the European Union. Huelva
offers adequate climatic characteristics and soil composition
as well as water disponibility for irrigation that is exceptional
in the national territory. Contemporany history of cultivating
strawberry de Huelva started in 60’s in Moguer city.
In recent years, several day-neutral varieties have been
introduced and different agro-techniques were standardized
at various research stations 2 . In addition, strawberry has
become the most favourite fruit crop among the growers,
especially near towns and cities, which has resulted a phenomenal
increase in its area and production. In Huelva,
many varieties of strawberry and raspberry are grown, but
(Fragaria vesca var. Camarosa and Rubus idaeus var. Glen
Lyon) has become the most popular dessert variety due to its
high production potential and because it is an attractive red
medium-sized fruit of better quality.
The safeguard of quality characteristics from harvest up
to consumption is an essential requirement for the fruit sector.
Quality control and authentication of fruits and derivatives
is a key aspect for consumers and producers. Food authentication
is the process by which a food is verified as complying
with its label description. Labeling and compositional
regulations, which may differ from country to country, have
a fundamental place in determining which scientific tests are
appropriate for a particular issue 3 Thus the availability of
sound analytical methods which can ensure the authenticity
of foods plays a fundamental role in the operation of modern
society. In this sense, several analytical parameters have to be
taken into account.
In this work, we have analysed several samples of
strawberries and raspberries (Fragaria vesca var. Camarosa
and Rubus idaeus var. Glen Lyon) in relation with phisicochemical
parameters (elements such as Ca, Mg, K, na, B,
Cu, Fe, ni and Zn; anions: phosphates, nitrates, sulphates,
carbonates; solids in suspension, pH, redox potential). The
experiment was carried out during six months in which several
agrochemical experiments have been developed such as
the use of new plastics for the harvest and the pollination
with bumblebees.
s733
Experimental
S a m p l e s
Samples of soils and leaves were analysed in this study.
The samples of leaves were taken during the months of major
production of both plants and the samples of soil at the beginning
and at the end of the harvest.
P r e p a r a t i o n o f t h e S a m p l e
(i) Samples of leaves: The samples were dried in an oven
at 100 °C. After that they were extracted by using a microwave
oven: 0.2 g of sample was weighted and 4 ml of HnO3 (65%) were added. The program was from room temperature
to 170 °C at 20 °C min –1 .
(ii) Samples of soil: the same parameters that for the
leaves were analyzed, but different extractant solutions were
used4,5 :
• Phosphorus: Extraction with sodium bicarbonate at pH
8.5
• Manganese and iron: Extraction with ammonium acetate
pH 4.8
• Sodium, potassium, calcium and magnesium: Extraction
with ammonium acetate at pH 7
• Organic matter: was determined by a redox process using
potassium dichromate and sulphuric acid, to measure the
excess of dichromate with a salt-ferrous
M e a s u r e d E l e m e n t s a n d M e t h o d s o f
A n a l y s i s :
63Cu and 66Zn: measured with an Inductively Coupled
Plasma Mass Spectrometry (ICP-MS) Model 4500
(Agilent Technologies, Tokyo, Japan)
Orthophosphates: measured with the molybdenum blue
method4 •
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• Mn, Fe, Ca, Mg: they were measured with Atomic
Absorption Spectroscopy (AAS).
• K and na: Atomic Emission Spectroscopy (AES).
• Determination of the soil texture: it was measured by
using the Mastersizer 2000, a laser diffraction instrument.
I C P - M S P a r a m e t e r s :
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RF power: 1,370 W
Plasma gas flow-rate: 15 dm 3 min –1
Auxiliary gas flow-rate: 1.00 dm 3 min –1
nebulizer gas flow-rate: 1.15 dm 3 min –1
Sampling depth: 6.5
Sampler and skimmer cones: ni
Time per isotope: 0.3 s per isotope
Isotopes monitorized: 63 Cu and 66 Zn
Results
The results of analyses of soil throughout the study are
collected in the Table I.
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At the beginning of the study (February).
At the end of the harvest, in June.