Investigating carotenoid loss after drying and storage of
Investigating carotenoid loss after drying and storage of
Investigating carotenoid loss after drying and storage of
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2. Assessment <strong>of</strong> Methods<br />
Therefore an average density <strong>of</strong> 4 kg.m -2 was the optimal density for <strong>carotenoid</strong> retention<br />
when <strong>drying</strong>.<br />
2.7.3 Influence <strong>of</strong> freeze-<strong>drying</strong><br />
Freeze <strong>drying</strong> was tested with the purpose to replace fresh roots by freeze dried sweet<br />
potato to facilitate air freight transport for analysis in UK or France (Table 2-10).<br />
Table 2-10: Losses <strong>of</strong> trans- "-carotene <strong>after</strong> freeze-<strong>drying</strong>. See HPLC method in<br />
section 2.3.3.<br />
Sample<br />
Trial 1:<br />
Rubina®<br />
Trial 2:<br />
Beauregard<br />
Size<br />
reduction<br />
5 mm thick<br />
slices<br />
pureed<br />
Treatment<br />
Dry matter<br />
content (%)<br />
Trans-!carotene<br />
content<br />
("g.g -1 )*<br />
Trans-!carotene<br />
<strong>loss</strong> (%)<br />
Fresh 18 250.4(8.8) -<br />
Freeze-dried 96.1 182.7(12.9) 27.0<br />
Fresh 15.9 380.2(36.1) -<br />
Freeze-dried 90.7 363.9(20.0) 4.3<br />
*On a dry weight basis. Each value corresponds to an average <strong>of</strong> two extractions. Values<br />
in brackets refer to the st<strong>and</strong>ard deviation.<br />
Five OSFP roots were peeled, roughly sliced (about 5mm) <strong>and</strong> freeze-dried (SMH15<br />
Model USIFROID, Maurepas, France). Trans-!-carotene content was measured on fresh<br />
<strong>and</strong> freeze dried samples (Table 2-10).<br />
In the trial 1, freeze-<strong>drying</strong> took 5 days due to bulkiness <strong>of</strong> the slices. A significant <strong>loss</strong><br />
in trans-β-carotene (27.0%) during freeze-<strong>drying</strong> was found. This result is in agreement<br />
with 25% <strong>loss</strong>es observed by Chavez et al. (2004) in freeze-<strong>drying</strong> <strong>of</strong> yellow cassava<br />
that contains !-carotene. The size <strong>of</strong> the chips was not mentioned however. In the trial 2,<br />
freeze-<strong>drying</strong> took two days. There was a minimal <strong>loss</strong> <strong>of</strong> trans-!-carotene (4.3%).<br />
Isomers <strong>of</strong> !-carotene were present in fresh <strong>and</strong> freeze-dried samples in similar amounts<br />
<strong>and</strong> no difference was observed between chromatograms <strong>of</strong> fresh <strong>and</strong> freeze-dried<br />
samples (data not shown). Significant <strong>loss</strong> observed in the first trial may be due to long<br />
time <strong>of</strong> freeze-<strong>drying</strong>. Parameters that influence the retention <strong>of</strong> <strong>carotenoid</strong>s in freeze-<br />
<strong>drying</strong> are the <strong>drying</strong> time, which related to the particle size. The second trial<br />
demonstrated that it was possible to preserve <strong>carotenoid</strong>s with the use <strong>of</strong> freeze dried
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