Selected nutritional quality and physicochemical properties of silkworm pupae (frozen or powdered) from two species

This research was performed to examine selected nutritional quality and physicochemical properties of silkworm pupae. Frozen or powdered pupae from two species of silkworm (Bombyx mori and Samia ricinii) were studied. Eri had the largest size with the highest lightness and peak viscosity. The PCA (principal component analysis) total variance could be explained by 74.68%, and silkworm pupaes could be put into 2 clusters. Cluster 1: all varieties of frozen silkworm pupae having a high moisture content; Cluster 2: silkworm pupae powder. Thai and Hybrid silkworm pupae powder had the highest calcium, total fat and n-3, n-6 and n-9 fatty acids. Eri silkworm pupae powder had the highest protein, essential amino acid and crude fibre. Each variety of silkworm pupae had different properties that might be suitable for developing different food products. Therefore, the presented data would be advantageous for manufacturers for developing functional ingredients and novel foods.     

Soy sauce odour induces and enhances saltiness perception

Developing products with reduced sodium content is one alternative for consumers interested in reducing their daily sodium intake. In this research, we determined whether soy sauce odour could induce and enhance salty taste perception in salt solution models. The sensory threshold technique (ASTM E679‐04, the ascending forced choice method of limits) was used to determine thresholds at 25 °C. Group best estimate threshold geometric means of soy sauce odour were expressed as parts‐per‐billion (ppb, v/v). At 28.45 ppb (recognition threshold), soy sauce odour could induce salty taste in 0.03 mm NaCl solution (in which salty taste was undetectable without soy sauce odour) and at 122.71 ppb (difference threshold), it enhanced salty taste (i.e. saltier) perception in 20 mm NaCl solution. Through the odour–taste interaction concept, this study demonstrated that the soy sauce odour could induce and enhance salty taste perception, which could be applied in the development of reduced‐sodium foods.     

Comparison of phenolic profiles and antioxidant potentials of the leaves and seeds of Thai holy and sweet basils

Eight phenolics rosmarinic, caftaric, caffeic, chicoric, p‐hydroxybenzoic, p‐coumaric, protocatechuic acid and rutin were identified in Thai holy/sweet basil leaves or seeds. The overall phenolics in THBL were two, three and twenty times higher than that in TSBL, THBS and TSBS, respectively. Oppositely, the TP content of TSBL was one and a half times higher than THBL which was followed by THBS and TSBS. The order of scavenging DPPH free radical activity from high to low was THBL, TSBL, THBS and TSBS and consistent with their overall phenolics. In a cholesterol oxidation model, THBL exhibited higher antioxidant activity with lower level of 7‐ketocholesterol (2.67 ± 0.31 μg/mL) than TSBL (4.49 ± 0.32), THBS (7.78 ± 1.25) or TSBS (13.10 ± 0.61). The results demonstrated that Thai holy basil has higher antioxidant capability than sweet basil and could be used as an effective bioactive ingredient to provide health‐promoting function in food.     

Physico‐functional and antioxidant properties of purple‐flesh sweet potato flours as affected by extrusion and drum‐drying treatments

Effects of extrusion and drum‐drying treatments on physico‐functional and antioxidant properties of flours prepared from purple‐flesh sweet potato were evaluated. Extrusion variables were feed moisture contents (MC; 10%, 13%, 16%) and screw speeds (SS; 250, 325, 400 r.p.m.), whereas drum‐drying was done at 120, 130 or 140 °C. Effects of MC were generally greater than SS on flour properties. Extruded flours showed higher water absorption and water solubility indices compared with control nonextruded flours. Regardless of SS, total phenolic content and antioxidant activities (DPPH and ABTS) of flours processed at 10% MC were significantly higher than those at 13% and 16%. Both extruded and drum‐dried flours exhibited no peak viscosity, indicating complete gelatinisation of starch. Maximum phenolic content and antioxidant activities of drum‐dried flours were obtained at 140 °C. Although drum‐dried flours had higher antioxidant capacity than extruded flours, both flours could potentially be used as food ingredients.     

Physicochemical properties of rice flour as affected by alkaline soaking and washing treatments

Effects of alkaline [NaOH, saturated Ca(OH)₂ and/or limewater] soaking and subsequent washing (with water vs. without washing) treatments on physicochemical properties of rice flour were investigated. Alkaline soaking treatment generally caused a loss of granule angularity but some birefringence was observed for unwashed alkali-soaked flour granules. After soaking, protein content of the flours significantly (P < 0.05) decreased but swelling power significantly (P < 0.05) increased compared to the control (soaked in water). The washed flours had lower protein content than unwashed flours (3.77–6.87% vs. 5.26–7.87%). The NaOH-soaking treatment yielded higher swelling power and solubility, respectively, for unwashed and washed flours. Alkaline soaking increased breakdown but decreased pasting temperature, trough viscosity, final viscosity and setback of the paste compared to the control. Compared to the control, hardness of soaked flour paste was lower due to lower final viscosity and setback. Overall, physicochemical properties of rice flour could be modified by alkali-soaking and washing treatments.     

Effects of cricket powder on selected physical properties and US consumer perceptions of whole-wheat snack crackers

Successful introduction of insect consumption to a reluctant US population requires novel insect-based foods that are responsive to consumers’ expectations of sensory quality. Based on our ‘product appropriateness’ data, snack crackers were formulated with increasing levels of cricket powder (0%, 5%, 10%, 15%, and 20%) in substitution of whole-wheat flour. Colour, texture, flavour and overall perceptions of snack crackers were evaluated by 150 US consumers in terms of preference (2-alternative choice), degree of liking (9-point scale) and acceptability (yes/no). Flavour liking was most highly correlated with overall liking (r = 0.93). Instrumental analyses indicated that increasing cricket powder resulted in darker and harder crackers, negatively impacting colour and texture preference at 5% and 15% cricket powder addition, respectively. Snack crackers remained acceptable at 15% wheat flour substitution (80% acceptability; mean overall liking = 5.5). However, to promote future consumption, an upper limit of 7.9% cricket powder addition is recommended until sensory quality can be improved.     

Novel peptides from dried squid head by-products obtained from snack process

The novel peptides were successfully produced with commercial protease hydrolysis (Alcalase® and Flavourzyme®) at the fixed concentration of 3%by weight of protein in substrate. The hydrolysis was performed at various hydrolysis times (0, 300, 450, 600 and 750 min) at the optimal pH and temperature. When the hydrolysis was performed until 750 min, the peptide solutions with high soluble protein content were resulted (47.58 and 42.53 mg protein per mL for Alcalase® and Flavourzyme® hydrolysis, respectively). After freeze drying, the peptide powder from Alcalase® and Flavourzyme® hydrolysis had degree of hydrolysis at 71.87% and 66.39%, respectively. Alcalase® hydrolysis provided the novel peptide fraction with DPPH scavenging, ABTS activity and ACE-inhibitory activity at 64.20%, 102.50 µg mL⁻¹ and 56.98%, respectively. This peptide fraction possessed the lowest molecular weight (m/z 807.418) as detected by MALDI-TOF/MS, and the most potent peptide sequence was Arg-Glu-Gly-Tyr-Phe-Lys which has the potential as functional ingredient in novel food, snacks and beverages.     

Concentrating sulphur-containing flavour from Toona sinensis shoots using corn oil with and without aqueous dispersion

Toona sinensis (TS) shoot is a seasonal and quick deteriorating vegetable with unique alliaceous flavour. In this study, corn oil was used to concentrate the sulphur-containing compounds responsible for the unique TS flavour with and without aqueous dispersion. The level of sulphur-containing compounds in TS shoots was 0.32 μg g⁻¹ and concentrated to 2.34 μg g⁻¹ in the corn oil with aqueous dispersion. The sulphur-containing compounds, trans-2-Mercapto-3,4-dimethyl-2,3-dihydrothiophene and (E,Z)-Di-1-propenyldisulphide, were identified in the corn oil, while they were not detected in the oil without aqueous dispersion. Based on sensory and electronic nose analysis, the aroma of corn oil with aqueous medium extraction had stronger alliaceous aroma than TS shoots and the extraction corn oil without aqueous dispersion. With aqueous dispersion assistance, the sulphur-containing aroma compounds in TS shoots were effectively concentrated in corn oil. The flavour-enriched oil could serve as a flavour ingredient to deliver TS shoots aroma for different food applications.