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IV. Resultados y discusión. Capítulo II 205
formulation of the fermented product was established on the basis of the
results obtained for the response variable.
2.3 Product characterisation
Both raw hazelnut milk and optimal fermented product stored for
different times were characterised as to their content in different sugars, pH,
acidity, rheological behaviour and colour. In hazelnut milk, the chemical
composition of major components (dry matter, protein, lipid, total sugars
and ashes) was obtained. Moreover, the fermented product was analysed
throughout the storage time (0, 1, 7, 14, 21 and 28 days) at 4ºC in terms of
probiotic survival before and after having submitted the samples to a
simulated gastrointestinal digestion (SGID), proteolytic activity, colloidal
stability and sensory attributes. All the analyses were done in triplicate.
2.3.1 Chemical analyses
AOAC official methods of analysis were used to determine moisture
(AOAC 16.006), total nitrogen (AOAC 958.48) and fat contents (AOAC
945.16) (Horwitz, 2000). Ashes were obtained following the protocol
reported by Matissek et al. (1998).
Sugar profiles were analysed and the different sugars were quantified using
the following HPAC-PAD equipment: Metrohm 838 Advanced Sample
Processor (Metrohm ® Ltd., Herisau, Switzerland) in an Advanced Compact
IC 861 ion chromatograph (IC) equipped with a pulsed amperometric
detector to monitor the separation (Bioscan 817). Prior to the analysis,
samples were diluted 1:100 with nanopure water. Sample proteins were