Acerola, Cashew Apple, Cherimoya and Pitanga - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 557

also had appreciably lower flavonol concentrations than
those of the unprocessed fruit (Hoffman-Ribani et al.,
2009).
Frozen acerola fruits lost 43% and 19% of the initial vi-
tamin C content during 4 months of storage at -12 ◦ and
-18 ◦ C, respectively (Yamashita et al., 2003). Pasteurized
frozen fruit pulp showed no significant reduction in this
vitamin over the storage period, the final levels being 1,314
and 1,322 mg/100 g when stored at -12 ◦ and -18 ◦ C, re-
spectively. In bottled pasteurized juice, the final vitamin C
content was 673 mg/100 g, representing a 32% loss over
4 months of ambient storage. A reduction of total antho-
cyanin and total flavonol in frozen pulp of acerola after 6
months of frozen (

Raw acerola fruit

Washing

Sorting

Pulping

Second pulping

Deaeration

− 18 ◦ C) storage was reported by Lima

et al. (2002).
In 27 samples of frozen pulp from the northeastern
Brazilian states of Pernambuco and Paraiba, pH varied from
2.5 to 3.27, soluble solids from 4.40 ◦ to 9.16 ◦ Brix, titratable
acidity (expressed as citric acid) from 0.47% to 1.29%, and
vitamin C from 470 to 1,655 mg/100 g (de Oliveira et al.,
1999). Eleven of the samples had at least one parameter
not in accordance with current Brazilian regulation for this
product. Despite apparent losses, the product remained a
rich source of vitamin C.
In recent years, acerola fruit has been focus of increased
research. Aside from determining composition, the stud-
ies focused on optimization of processing and the appli-
cation of new technologies. Oliva et al. (1996) studied
the processing of acerola nectar using two thermal pro-
cesses: a plate heat exchanger, followed by hot filling, and
a spin-cooker-cooler. The temperature and time for pas-
teurization in both processes (88 ◦ C for 45 sec) were ad-
equate to ensure microbiological, chemical, and sensory
stability. Loss of ascorbic acid was greater in the plate
exchanger-hot filling processing. Compared to storage at
8 ◦ C, storage at ambient temperature resulted in greater loss
of ascorbic acid and alterations in the other parameters
studied (flavor, color), regardless of the thermal processing
applied.
Microfiltration with enzymatic hydrolysis resulted in
clarified and concentrated acerola juice with high nutri-
tional, sensory, and microbiological quality (Matta et al.,
2004). Microfiltration was efficient in removing substances
that cause haze and reduced yeast and mold counts. The
procedure consisted of pulping, enzymatic hydrolysis, mi-
crofiltration, and concentration by reverse osmosis (6 MPa
transmembrane pressure). The vitamin C content was
1,234 mg/100 g in the hydrolyzed juice, 1,234 mg/100 g in
the clarified juice, reaching 5,229 mg/100 g in the concen-
trated juice.

Cooling Juice deaeration

Thermal treatment

Packaging/Sealing

Aseptic packaging

Freezing (-20°C)

Storage (-20°C) Storage

Figure 29.3. Flow diagram of the preparation of
acerola frozen pulp and aseptically-packaged juice.

Processed juice is either aseptically packaged or bottled
(hot filled). The aseptically packaged juice is processed
according to steps shown in Figure 29.3. The pulp is sub-
mitted to a second pulping in a finisher with 0.5 mm diam-
eter mesh. Air incorporated in this step is also removed by
vacuum.
Heat treatment is carried out in a heat exchanger with a
heat regeneration system. The temperature of the pulp as it
goes out of the equipment is about 20 ◦ − 30 ◦ C. The juice is
packed under aseptic conditions in 250 ml Tetrapak cartons
and can be stored at 20 ◦ − 25 ◦ C.

Effects of processing on quality
Variable and markedly lower carotenoid levels were ob-
tained by Porcu and Rodriguez-Amaya (2006) in four
brands of frozen pulp and three brands of bottled juice,
compared to the fresh acerola, indicating that the current
commercial processing should be improved. Mezadri et al.
(2006) reported geometric ( E to Z ) isomerization and trans-
formation of 5,6- to 5,8-epoxides.
Processed products (ready-to-drink juice, concentrated
juice, frozen pulp) of acerola, cashew apple, and pitanga