for the conventional and combined c

for the conventional and combined conventional-vacuum processes respectively, and 1.6–3.8 min for the vacuum process (Table 1). Roasting of coffee under different pressure conditions was also responsible for different rates of browning.Fig. 2shows the lightness and hue angle changes of coffee beans subjected to conventional, combined conventional-vacuum and vacuum roasting
processes as a function of theFvalue. As known, a decrease in these two colour parameters is an index of browning development due to the formation of melanoidins (i.e. the brown polymers that
are formed during the final stage of the Maillard reaction). Only slight differences in lightness (Fig. 2a) were observed among the different samples. By contrast, the decrease in hue angle (Fig. 2b)
was greater in the vacuum-processed coffee up to anFvalue of
approximately 3.8 min. At increasingFvalues, browning was significantly higher for the conventionally roasted coffee. Nevertheless, these differences in hue angle were almost not appreciable
by visual observation of the medium and dark roasted ground samples (Table 2).
Fig. 3shows the changes of acrylamide concentration in coffee
beans subjected to conventional, combined conventional-vacuum
and vacuum roasting as a function ofF. As is well known, the
amount of acrylamide increases exponentially with roasting time,
reaches a maximum and then decreases rapidly (Bagdonaite, Derler, & Murkovic, 2008; Guenther et al., 2007; Lantz et al., 2006;
Taeymans et al., 2004; Senyuva & Gökmen, 2005). Such a decrease
0
100
200
300
400
500
600
700
800
900
1000
0 5 10 15 20 25 30
Acrylamide (ng/gdm
)
F(min)
convenonal
combined
vacuum
Fig. 3.Acrylamide concentration of coffee beans subjected to conventional,
combined conventional-vacuum and vacuum roasting as a function of the thermal
effect (F).
0
2
4
6
8
10
Odor intensity
conventional
vacuum
b’
a’ a a
dark-roasted medium-roasted
Fig. 4.Odour intensity of coffee powders medium or dark roasted under conventional (reference) and vacuum conditions. Within each degree of roast, different
letters indicate significant difference (p< 0.05).
Table 2
Images of ground coffee subjected to conventional, combined conventional-vacuum and vacuum roasting up to medium and dark degrees of roast. The corresponding thermal
effects (F) are also reported.
Degree of roast Conventional
roasting
Combined
conventionalvacuum roasting
Vacuum roasting
medium
F=3.9 min F=4.2 min F=3.8 min
dark
F=18.2 min F=19.9 min F=19.8 min
M. Anese et al. / Food Chemistry 145 (2014) 168–172 171
occurs when the rate of degradation exceeds the rate of formation,
probably due to the reaction of acrylamide with other reactive species present in the coffee (Biedermann, Biedermann-Brem, Noti, &
Grob, 2002). Recently, Pastoriza, Rufián-Henares, and Morales
(2012)stated that acrylamide may react with coffee melanoidins
during roasting, leading to a net decrease in acrylamide content.
In our experimental conditions, differences in acrylamide formation and reduction among the roasting processes considered were
observed (Fig. 3). In particular, acrylamide concentration in the
vacuum-roasted coffee sharply reached a maximum at anFvalue
of 1.6 min and then decreased. In the case of the conventional
and combined conventional-vacuum roasting, a maximum acrylamide formation was attained at F values ranging from 1.5 to
4.2 min. No significant differences in acrylamide concentration
among the coffee beans roasted according to the different processes were found atFvalues higher than 15 min. These differences in acrylamide reduction of coffee beans subjected to
roasting under the different pressure conditions adopted can be
attributable to a stripping effect exerted by the low pressure generated inside the oven during the vacuum process towards water
as well as water-soluble low-molecular-weight compounds,
including volatile compounds and acrylamide. Such a stripping effect would prevent acrylamide from being accumulated.
In order to study the effects of roasting under low pressure conditions on coffee quality, sensory analysis was carried out by sniffing
ground coffee subjected to conventional, combined conventionalvacuum and vacuum roasting with weight losses of about 7.0% and
13.5%, accounting for medium and dark degrees of roast, respectively (Fig. 4). It can be observed that the medium-roasted coffee
samples obtained by means of the conventional and vacuum processes and having different acrylamide levels, were not perceived
as different by the assessors. On the contrary, the vacuum darkroasted coffee was judged to present a slightly but significantly lower odour intensity with respect to the reference (conventionally
roasted) sample. No significant differences were found between
the dark-roasted coffees subjected to the conventional and combined conventional-vacuum processes (data not shown).
4. Conclusion
Roasting under low pressure conditions gave medium-roasted
coffee with 50% lower acrylamide levels, as compared to the conventionally roasted coffee, with minimal impact on the sensory
properties. Although further research should be conducted at pilot
and industrial scale to find optimum process conditions, these results suggest that vacuum roasting could have a great economic
impact, as medium-roasted coffee generally has higher acrylamide
levels than dark-roasted coffee. Indeed, from the industrial point of
view, safety could be a new factor influencing coffee commercial
opportunities, especially for the American and North European
markets, where medium-roasted coffee consumption, and thus
acrylamide intake, are relatively high

Hasil (Bahasa Indonesia) 1:

pengobatan, constantFvalue, berat kerugian selama vakumproses pembakaran secara signifikan lebih tinggi daripada yang terjadi selama konvensional dan gabungan konvensional-vacuum memanggang. Hal ini dapat disebabkan oleh resistansi yang lebih rendah dari air untuk melarikan diri, dihasilkan oleh tekanan sangat rendah di dalam oven. FromTable 1it dapat dicantumkan bahwa biji kopi yang mengalami konvensional, dikombinasikan vacuum konvensional dan vakumproses mencapai sebanding berat kerugian di similarFvalue sekitar 20 menit, yang dilakukan di 30, 40 dan 45 min memanggang, masing-masing. Menurut literatur (Clarke,1987), nilai ini hilangnya berat berpadanan dengan gelar gelap panggang. Perlu dicatat bahwa tingkat menengah panggang, akuntansi untuk kerugian berat mulai dari 6% sampai 8% (Clarke, 1987), adalahdicapai dengan applyingFvalues sekitar 4.2 dan 3.9 min

Hasil (Bahasa Indonesia) 2:

pengobatan, untuk constantFvalue, kerugian berat badan selama vakum
proses pemanggangan secara signifikan lebih tinggi daripada yang terjadi selama pemanggangan konvensional-vakum konvensional dan gabungan. Hal ini dapat disebabkan oleh resistensi yang lebih rendah dari air untuk melarikan diri, yang dihasilkan oleh tekanan yang sangat rendah di dalam oven. 1it FromTable dapat dicatat bahwa biji kopi dikenakan, konvensional-vakum dan vakum gabungan konvensional
proses mencapai kerugian berat dibandingkan pada similarFvalue sekitar 20 menit, yang dicapai pada 30, 40 dan 45 menit pemanggangan, masing-masing. Menurut literatur (Clarke,
1987), ini nilai penurunan berat badan berhubungan dengan tingkat gelap panggang. Perlu dicatat bahwa tingkat menengah panggang, akuntansi untuk kerugian berat mulai dari 6% sampai 8% (Clarke, 1987), yang
dicapai dengan applyingFvalues ​​sekitar 3,9 dan 4,2 menit