Low-sodium roasted peanuts: effects of salt mixtures (NaCl,KCl and glycine) on consumer perception and purchase intent

The effects of ten treatment combinations of two salts (NaCl, KCl) and glycine were evaluated on low-sodium roasted peanuts. Consumers’ (N = 330, recruited from college campus) liking, emotions, perceived saltiness and bitterness intensity, satisfaction and purchase intent (PI) of peanuts were measured following a balanced incomplete block design (t = 10, k = 3, r = 9, b = 30, λ = 2, e₂ = 0.74). Emotions and PI were evaluated both before and after presenting a low-sodium health benefit message. Sodium content of peanuts was reduced from 140 mg Na/50 g peanuts to 41.67 mg Na/50 g without significantly affecting liking scores and with positive PI over 60%. In general, high bitterness and low saltiness intensity ratings negatively affected liking and satisfaction. Consumers expressed less satisfaction when perceived saltiness intensity was ‘Not Enough’ than when ‘Too Much.’ Based on optimisation analysis, any formulation within the range of 59-100/0-40/0-12.5% NaCl/KCl/Gly- representing a potential 37% sodium reduction past minimum ‘low sodium’ requirements- will yield an acceptable product.     

An improved determination method for tyramine in foods using ultra-high performance liquid chromatography with benzylamine as internal standard

Tyramine has been considered a biological hazard for foods and beverages. In this study, an ultra-high pressure liquid chromatography (UPLC) with benzylamine as an internal standard in dansyl chloride pre-column derivatisation was developed to determine tyramine in various foods. Different from other tyramine determination methods usually without an internal standard in the pre-column derivatisation, benzylamine which chemical structure is similar to tyramine was selected as an internal standard. The limits of detection and quantification of this method were 0.05 and 0.25 mg L⁻¹, respectively, while the relative standard deviations of repeatability and reproducibility were 2.1% and 3.1%, respectively. The sensitivity and reliability of this method were also evaluated by determining tyramine in common liquid, pasty and solid foods. The recoveries of tyramine in these foods were between 87.3% and 96.8% by using this method. Overall, it is a fast, inexpensive, reliable and sensitive method to measure tyramine in different food products.     

Antimicrobia activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils applied by liquid vs. vapour phases

Antimicrobial activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils (GEO and HBEO, respectively) was evaluated in liquid vs. vapour phases. Diallyl disulphide and diallyl trisulphide in GEO while eugenol, caryophyllene and methyl eugenol in HBEO were predominant active compounds. Individually, GEO was highly effective in the vapour phase, showing the greatest antimicrobial activity (P ≤ 0.05) against Bacillus cereus and Staphylococcus aureus with complete inhibition, followed by Salmonella typhimurium and Pseudomonas fluorescens, but had no effect on Escherichia coli, Lactobacillus plantarum or Listeria monocytogenes. The combined GEO:HBEO (a 1:1 ratio) at 30 μL demonstrated inhibitive activity against all bacteria tested with complete inhibition against B. cereus and S. aureus. Minimum bactericidal concentration (MBC) of the combined oil was <0.4% v/v, except for P. fluorescens requiring a higher MBC (1.5%, v/v). This study demonstrated potential of the combined GEO:HBEO to be used for food preservation applications.     

Product appropriateness,willingness to try and perceived risks of foods containing insect protein powder: A survey of U.S. consumers

As a sustainable alternative to livestock consumption, insect protein has applications beyond meat substitution. However, strategies to normalise entomophagy in the United States have been less explored than in Europe. Two online surveys (N = 1005 U.S. consumers) identified the most appropriate products, from a list of 30, for insect protein powder incorporation by evaluating willingness to try (WTT). Consumers reported perceived risks for negative WTT, and the effect of entomophagy benefit information (EBI) on WTT was measured. Overall, 72% of consumers were willing to consume at least one insect-containing product. The three most appropriate products were protein/energy bars, chips/snack crackers and protein shakes. Bakery/cereal products garnered positive WTT by >54% of consumers, followed by snacks/candy (53%). Unfamiliarity with insects as food was the most cited risk. EBI presentation significantly increased (α < 0.05, McNemar’s test) positive WTT for all products. Once unfamiliarity is overcome through trial, negative emotions and concerns about sensory quality can be addressed.     

Physicochemical and functional properties of chitosans affected by storage periods of crab leg shell

Effects of storage period (0, 1, 2, 3 and 4 months) of crab leg shell at room temperature on selected physicochemical and functional properties of E‐ and G‐chitosans, respectively, prepared from entire (E) and ground (G) shells were evaluated. Increased storage period of crab shell generally increased degree of deacetylation (DD) and viscosity, but decreased DPPH radical scavenging activity of both chitosans. Water‐binding (WBC) and fat‐binding (FBC) capacities of E‐chitosan were not affected by storage period of crab shell; however, those of G‐chitosan significantly increased when crab shell was stored for more than 1 month. Dye‐binding capacity (DBC) of both chitosans decreased when crab shell was stored for 1 month, but further decrease was not observed with increased storage period to 4 months. Prepared with 4‐month stored crab shell, E‐chitosan exhibited comparable viscosity, colour whiteness index, DPPH radical scavenging activity and DBC, but lower DD, WBC and FBC than G‐chitosan.     

Butterfly pea (Clitoria ternatea) seed and petal extracts decreased HEp‐2 carcinoma cell viability

The hydrophilic phenolics, lipophilic tocopherols, phytosterols and fatty acids in butterfly pea seeds and petals were determined. The seeds had fifteen phenolics; of them, sinapic acid, epicatechin and hydroxycinnamic acid derivative concentrations were above 0.5 mg g^?1. The petals contained a group of ternatins, flavone glycosides and delphinidin derivatives. Both the seeds and petals had four phytosterols and α‐ and γ‐tocopherols. However, the level of β‐sitosterol or γ‐tocopherol in the seeds was much higher than in the petals. Linoleic acid was the most abundant fatty acid in the seeds and petals, while phytanic acid was found in the petals. The effect of lipophilic and hydrophilic extracts of the seeds [lipophilic extract of the butterfly pea seeds (LBS) and hydrophilic extract of butterfly pea seeds (HBS)] and petals [lipophilic extract of the butterfly pea petals (LBP) and hydrophilic extract of butterfly pea petals (HBP)] on decreased HEp‐2 human carcinoma cell viability was evaluated. The effect of HBS or HBP on decreased cancer cell viability was much higher than that of either LBS or LBP, while HBS showed significantly higher effect than HBP. The results indicated that butterfly pea seed and petal extracts could have the potential in functional food development.     

Assessment of the ability of five culture media for the detection of Escherichia coli O157

Cattle are a common reservoir for Escherichia coli O157:H7. Prior to confirming its presence in a sample, proper isolation of E. coli O157 is necessary. Consequently, this study evaluated the ability of five commercial plating media to isolate E. coli O157 from 138 samples of fresh cattle faeces, water from water trough and pond, and surfaces of water trough and hay bunk. For the isolation of E. coli O157, samples were enriched in tryptic soya broth, followed by immunoseparation and then plating on SMAC, CT‐SMAC, CHROMagar^? O157, Tellurite CHROMagar^? O157 and Vancomycin Cefixime Cefsoludin CHROMagar^? O157. Real‐time PCR targeting genes stx₁, stx₂ and wzy_O157 was used to confirm selected isolates. When analysed together, CT‐SMAC and CHROMagar^? O157 were the best combination for isolating E. coli O157, giving 79% true‐positive results and only 0.05% false‐negative results.     

Antibacterial activity of chitosans with different degrees of deacetylation and viscosities

Antibacterial activities of six acid‐soluble [two degrees of deacetylation (DD) × three viscosities] and two water‐soluble chitosans (two DD with similar viscosities) were examined against eight gram‐negative (Pseudomonas fluorescens, Proteus vulgaris, Erwinia carotovora, Serratia marcescens, Escherichia coli, Vibrio parahaemolyticus, V. vulnificus, and Salmonella Typhimurium) and six gram‐positive bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, B. cereus, Lactobacillus curvatus, and L. plantarum). Antibacterial activities of chitosans differed depending on the chitosan types and bacteria tested. Water‐soluble chitosans inhibited bacterial growth by one to eight log cycles at 0.1% concentration; however, the effects were much lesser than those observed with 0.05% acid‐soluble chitosans. Minimum inhibitory concentration (MIC) values (0.03% to above 0.1%) of acid‐soluble chitosans were much lower than those (0.05% to above 0.8%) of water‐soluble chitosans. Based on MIC values, the acid‐soluble chitosan with 99% DD and lower viscosity (17.9 mPa s) was most effective in inhibiting bacteria growth among eight chitosans tested.     

Polyethyleneimine-loaded bimodal porous silica as low-cost and high-capacity sorbent for CO2 capture

In this work, bimodal (meso-macro) porous silicas with different mesopore diameters synthesized by using rice husk ash as a low-cost silica source and chitosan as a natural template were used as a polyethyleneimine (PEI) support for CO₂ capture. Unimodal porous silica supports with equivalent mesopore diameters to bimodal porous silica supports have been prepared for purpose of comparison. Effects of different PEI contents (10, 20, 30, 40 and 50 wt%) on CO₂ sorption capacity have been systematically investigated. The porous silica supports and the PEI-loaded porous silica supports were characterized by N₂-sorption analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and thermal gravimetric analysis. CO₂ sorption measurements of all PEI-loaded porous silica supports were performed at different adsorption temperatures (60, 75, 85, 90, 95 and 105 °C). At low PEI contents (10–20 wt%), the CO₂ sorption of all adsorbents was found to decrease as a function of adsorption temperature, which was a characteristic of a thermodynamically-controlled regime. A transition from the thermodynamically-controlled regime to a kinetically-controlled regime was found when the PEI content was increased up to 30 wt% for PEI-loaded unimodal porous silicas and 40 wt% for PEI-loaded bimodal porous silicas. At high PEI contents (40–50 wt%), the CO₂ capturing efficiency of the PEI-loaded bimodal porous silicas was found to be considerably greater than that of the PEI-loaded unimodal porous silicas, indicating that most of the amine groups of PEI molecules loaded on the unimodal porous silica supports was useless, and thus the appeared macroporosity of the bimodal porous silica supports could provide a higher effective amine density to adsorb CO₂.