Slide 1

Hii, Law - Quality Evolution During Drying of FVFs

astringency have been correlated to the content of volatile acids and polyphenols in co-
coa beans (Jinap and Zeslinda, 1995; Luna et al., 2002). Theobromine and caffeine con-
tribute to bitterness during sensory evaluation (Ney, 1992). The presence of aldehydes,
alcohols and ketones could produce several odours to rice such as fruity, woody, green,
pungent, sweet, citrus, spicy, fragrant and etc (Sunthonvit et al., 2003).

Figure 6. 3. Some selected sensory attributes of food products

6. 3. EFFECT OF DRYING ON PRODUCT QUALITY

All food quality attributes (e.g. texture, colour, flavour and nutrients) are affected by
drying conditions and processing parameters. In recent years various emerging drying
technologies and strategies have been developed to improve product quality such as by
using spray freeze drying (Leuenberger et al., 20 06 ), intermittent drying (Chua et al.,
2002 ), microwave assisted drying (Orsat et al., 2007) and superheated steam drying
(Devahastin and Suvarnakuta, 2004).

Several papers have provided comprehensive review on the effect of drying on
product quality (Mayor and Sereno, 2004; Santos and Silva, 2008; Sablani, 2006; Perera,
2005 ; Rahman, 2005). Table 6. 8 shows some selected examples of effect of drying pa-
rameters on product quality.

Table 6. 8. Selected examples on the effect of drying on product quality

Quality
attributes

Products Findings References

Various Fish mus- Size reduction in length (5-10%), width Pinto and Tobinaga

Odour

• Sharp


• Pun-
  gent


• Acid


• Sweet

Flavour

• Pun-
  gent


• Sweet


• Acid


• Bitter

Aftertaste

• Continui-
  ty

Texture

• Elastic


• Soft


• Hard


• Floury


• Sandy


• Lumpy


• Crystals


• Coarse


• Melting


• Moist


• Liquid


• Doughy


• Plastic


• Brittle


• Dry

Sensory attributes