Effect of roasting conditions on color development and Fourier transform infrared spectroscopy (FTIR-ATR) analysis of Malaysian-grown tropical almond nuts (Terminalia catappa L.)

Abstract

BackgroundProper roasting is crucial to flavor, color, and texture development in the final product. In recent years, several research studies have been carried out to establish the best optimum roasting conditions for some common edible nuts such as; hazelnut, peanut, and pistachio nut. Although roasting is an important process for nuts and oilseeds, there is little or no information on the development of color, aroma, and textural changes in Terminalia catappa nuts during roasting.ResultsResults showed that color formation and browning index were significantly (P < 0.05) influenced by the roasting temperature and time of roasting. However, the fracturability of nuts was significantly (P < 0.05) affected by both temperature of roasting and time as well as pH. The optimized results showed that the best response was reached when the roasting time was 29.9 min, roasting temperature 174.5°C, and pH 6.08, respectively. Moreover, the 3400–1560 cm−1 carbonyl region for carboxylic acid, alkenes, esters, and amines was found to provide a flavor-print of the roasted tropical almond nut. While, increase in temperature did not produce new carbonyl compounds, it however led to higher concentration of compounds. Scanning electron microscopy of the almond nuts showed that the starch granules were embedded in tissues.ConclusionThese results showed that roasting temperature and time of roasting were the main variables that significantly affected the physicochemical properties of roasted tropical almond nuts. Moreover the flavor-prints for the roasted nut were produced in the 3400–1560 cm−1 carbonyl region.Graphical AbstractEffect of roasting conditions on fracturability and structural morphology of tropical almond nuts (T. catappa).

Effect of pretreatment on the proximate composition, physicochemical characteristics and stability of <em>Moringa peregrina</em> oil

“…The change in the color of the oil due to germination could be due to the increase in the content of chlorophylls and carotenoids, which are synthesized during the different stages of the germination process (Herchi et al, 2015). In the case of roasting, the increase in the intensity of the oil's color may be due to Maillard-type non-enzymatic reactions between reducing sugars and free amino acids or amides during roasting, which lead to the formation of browning substances (Ng et al, 2014;Lee et al, 2015). Lee et al, (2015) investigated the Maillard reaction products of perilla oil at different roasting conditions.…”

“…The concentrations of both 2-methylpyrazine and 2,5-dimethylpyrazine increased gradually with increasing roasting temperature and time at first and decreased at higher temperatures whereas the concentrations of the last three compounds were increased with increasing roasting temperature and time. Furthermore, it is also known that (Ng et al, 2014) the roasting process results in a chemical reaction of phospholipid compounds and this enhances the development of brown pigments. Compared to the oil from the raw sample, the viscosities of the oils from roasted and germinated samples were changed significantly (p < 0.05).…”

Physicochemical quality and volatile flavor compounds of hot air‐assisted radio frequency roasted almonds

“…Color and texture are two most important quality parameters for roasted nuts. Color of almonds roasted at different degree was significantly different ( p < .05), and the color turned dark along with increasing roasting intensity, similar results were also reported by Ng, Lasekan, Muhammad, Sulaiman, and Hussain (). According to consumer sensory evaluation results shown in Figure , there was no significant difference ( p > .05) in the color between almonds roasted at light degree and medium degree.…”

Production and characterization of absorbent heat from the bark of residual Brazil nut bark (Bertholletia Excelsa l.)

“…The surface functional groups of AC2 were determined by Fourier transform infrared spectroscopy, (FTIR) and by Boehm method [19–22]. FTIR was carried out using the Thermo Scientific Nicolet apparatus, model IS10-USA in the region 4000-400 cm -1 .…”

“…The amount of phenolic groups were found by the difference between groups found in titration tests with sodium hydroxide (NaOH) and sodium carbonate (Na 2 CO 3 ), and lactonic groups by the difference of the groups found in tests with sodium carbonate (Na 2 CO 3 ) and potassium hydrogen carbonate (KHCO 3 ). To calculate the mass of acidic surface functional groups by Boehm method, Equation 1 was used [19–22]:…”