The effects of hot air, microwave, and combined microwave/hot air roasting on physical and chemical properties of carob powder were determined. The comparison of different roasting processes was evaluated whether the combined microwave/hot air roasting could be an alternative to other roasting methods or not. The moisture content (2.86%–5.03%), water activity (0.20–0.35), and pH (4.94–5.12) values of the carob powder decreased by increasing microwave power and roasting time; whereas total phenolic content (10.13–13.74 mg/g dm), total antioxidant activity (0.69–1.53 g/mg DPPH), browning index (23.57–70.30), and UV absorbance (427.41–701.05) increased. Hunter L (41.54–55.28) and b (16.45–20.91) values of the carob powder decreased after roasting while color value a (8.88–20.91) increased. The main sugar was sucrose (317.54–347.68 mg/kg), followed by fructose (80.98–90.11 mg/kg), and glucose (45.16–62.19 mg/kg). Roasting process reduced the sugar content while increased the d‐pinitol (62.41–76.71 mg/kg) content. The main volatile was isobutyric acid (acidic/butter odor). Hot air and the combined microwave/hot air roasted samples showed similar volatile and sensorial profile. According to the results, the combined microwave/hot air roasting consumed 50% less energy than the hot air roasting and got the best sensory scores.
Practical applications
The effects of microwave, hot air, and the combined microwave/hot air roasting processes on the properties of carob powder were first investigated. d‐pinitol content of carob was increased by roasting processes. Different roasting processes increased organoleptic properties of carob powder. Total phenolic content and antioxidant activity of carob powder increased by roasting. The combined microwave/hot air roasting consumed 50% less energy than the hot air roasting and it is recommended to produce carob powder with preferable product quality.
Apricot kernel (AK) is a by‐product of dried apricot rich in oils, proteins, carbohydrates, and minerals. However, despite its rich content, it is generally discarded after apricot processing. This study aims to expand the usage areas of AK with rich content and offer new alternatives to coffee consumers. Various concentrations of powdered AK were added in Turkish coffee (mixture: AKTC) to improve product flavor and increase nutritional and functional properties. After cooking, some physicochemical analysis and storage stability of AKTC were evaluated. With the addition of AK, the phenolic content of TC increased approximately two times. Also, the addition of AK increased the antioxidant activity of TC by about 15%. Acrylamide content of TC was decreased from 131.36 ± 3.13 μg/kg to 82.55 ± 2.13 μg/kg by adding more AK. Panelists gave higher scores to AKTC compared to TC. According to the storage stability analyses, adding AK increased the storage stability of the pure Turkish coffee.
Novelty impact statement
The dried apricot by‐product was first used for the fortifying of Turkish coffee, and the usage area of the apricot kernel, a high value‐added waste, was expanded. The acrylamide level of the Turkish coffee was reduced by adding apricot kernel powder. The shelf life of Turkish coffee as extended by adding apricot kernel powder.
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