title: 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: BACKGROUND
  Proper 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.
  
  
  RESULTS
  Results 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.
  
  
  CONCLUSIONS
  These 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).
authors.affiliation: Department of Food Technology, Faculty of Food Science and Technology, University Putra Malaysia, UPM, 43400 Serdang, Malaysia.
authors.forename: Siewsee
authors.initials: S
authors.lastname: Ng
authors.affiliation: Department of Food Technology, Faculty of Food Science and Technology, University Putra Malaysia, UPM, 43400 Serdang, Malaysia.
authors.forename: Ola
authors.initials: O
authors.lastname: Lasekan
authors.affiliation: Department of Food Science, Faculty of Food Science and Technology, University Putra Malaysia, UPM, 43400 Serdang, Malaysia.
authors.forename: Kharidah
authors.initials: K
authors.lastname: Muhammad
authors.affiliation: Department of Food Technology, Faculty of Food Science and Technology, University Putra Malaysia, UPM, 43400 Serdang, Malaysia.
authors.forename: Rabiha
authors.initials: R
authors.lastname: Sulaiman
authors.affiliation: Department of Food Technology, Faculty of Food Science and Technology, University Putra Malaysia, UPM, 43400 Serdang, Malaysia.
authors.forename: Norhayati
authors.initials: N
authors.lastname: Hussain
keywords: Fourier transform infrared spectroscopy; Response surface methodology; Roasting; Scanning electron microscopy; Terminalia catappa