Food Science and Technology International

Peanut, sesame, and (peanut:sesame (1:1)) meal milk were used as the egg yolk substitute at the levels of 0%, 25%, 50%, 75%, and 100% in mayonnaise. Then, the rheological, textural (hardness, adhesive force, and adhesiveness), and microstructural properties of samples were evaluated on the first day after production. The oscillatory test indicated that all treatments had shear thinning flow behavior and in low-angular frequencies had higher elastic modulus than the viscous modulus (tan δ < 1), but in the P-S50 and P-S100, P75 and S75 in angular frequencies higher than 63 rad.s⁻¹, tan δ was more than one (i.e. G″ > G′) which indicated more viscous modulus (liquid-like flow behavior) than the elastic modulus (gel-like flow behavior). The optical microscopy confirmed that the oil particle size in blank, 25 and 50% of substitution was of smaller size, and the fat droplets had a monotonous and regular form. In 75 and 100% of substitution, the oil particle size was larger and more irregular than the other ones. Therefore, considering the emulsifying characteristic of oilseeds proteins, consumer health aspect (replacing meal protein with egg yolk in producing of low-cholesterol mayonnaise), and economic advantage aspect (reusing the oil-extraction factories by-products i.e., meal) using oilseed meal milk as an emulsifier agent in food industries especially emulsions is purposed.

Valorisation of an agroindustry by-product, through its uses as an ingredient, in the development of a product may be an opportunity for industries to reduce wastes; generating a valuable product rich in bioactive compounds. Nevertheless, as happens with every new product, food manufacturers follow the market trend ensuring that any new product or idea meets consumer’s expectations. The aim of this work is to study the expectation and the acceptability of consumers towards fibre-enriched cookies using blueberry pomace as a functional ingredient. A label for the blueberry cookies, created for this purpose, was evaluated by consumers who rated their expected liking when observing this label. Fibre-enriched cookies were formulated using blueberry pomace powder as source ingredient for antioxidant dietary fibre. A cookie without fibre was evaluated as a reference. Cookies were evaluated by a group of consumers who rated their degree of liking when tasting the sample under blind and informed conditions. Results showed that the consumer expectations were not fulfilled when assessing the product. Acceptability scores of blueberry pomace, fibre-enriched cookies show that most consumers are not willing to compromise hedonic aspects of cookies for their healthful attributes. Focus group was used to explore the characteristics a healthy cookie should have. Formulation of cookies must be optimised taking into account the acceptability of consumers.

Aspergillus flavus is the potential pathogenic mold in red pepper powder (Capsicum annuum L.) and gochujang (red pepper paste), which can produce mycotoxins. This study investigated the effects of gamma ray, e-beam, and X-ray irradiation on the reduction of A. flavus on red pepper powder and gochujang and physicochemical and sensory quality changes. Gamma ray and e-beam at 3.5 kGy reduced A. flavus effectively (>4 log), without deteriorating the physicochemical quality. Same dose of X-ray did not cause any deterioration of the physicochemical quality. However, reduction effect of A. flavus in red pepper powder and gochujang by 3.5 kGy X-ray was under 2 log. Further, sensory quality analysis showed no significant difference in color, appearance, texture, and overall acceptability after three irradiations. However, flavor changes of red pepper powder and gochujang after three irradiations were mentioned by panelists. In this study, gamma ray and e-beam irradiation were effective in eliminating A. flavus present in red pepper powder and gochujang, but X-ray irradiation was not effective. The results indicate gamma ray and e-beam are effective in controlling microorganisms present in powdery or paste foods, but the X-ray was not effective.

Frozen sour cherry juice concentrates having 15%, 30%, 40% and 50% total soluble solid (TSS) contents were thawed by ohmic thawing (OT; 10 V/cm, 15 V/cm and 20 V/cm) and conventional thawing (CT; at 4 ℃). To enhance the electrode-sample contact during OT, the thawing cell was custom-designed. Thawing times were shortened about 90% by OT. Thermal images were taken to determine temperature homogeneity. As OT proceeded, a small amount of frozen sample having a relatively lower density raised up to the surface of the sample. It resulted in temperature heterogeneity in the surface due to relatively rapid temperature increment in thawed regions during OT. The change of effective electrical conductivity (EEC) in the temperature range of −18 ℃ and 4 ℃ was determined and it varied between 0.005 and 0.25 s/m. For the same temperature, EEC increased as TSS increased up to 40% (p<0.05). EEC–temperature relations were characterized by a polynomial model.

Spoilage caused by yeasts is a constant, widespread problem in the beverage industry that can result in major economic losses. Fruit juices provide an environment that allows the proliferation of yeast. Some factories in South Africa are not equipped with laboratory facilities to identify spoilage yeasts and outsourcing becomes a prolonged process which obstructs corrective action planning. This study aimed to establish yeast diversity and apply a rapid method for preliminary identification of spoilage yeasts associated with a small-scale fruit juice bottling factory. Yeast population in the factory was determined by isolation from the production environment, process equipment and spoiled products. PCR-RFLP analysis targeting the 5.8S-ITS region and D1/D2 sequencing was used for identification. A total of 207 yeasts belonging to 10 different genera (Candida, Lodderomyces, Wickerhamomyces, Yarrowia, Zygosaccharomyces, Zygoascus, Cryptococcus, Filobasidium, Rhodotorula/Cystobasidium and Trichosporon) were isolated and identified from the production environment and processing equipment. Candida intermedia, C. parapsilosis and Lodderomyces elongisporus were widely distributed in the factory. Zygosaccharomyces bailii, Z. bisporus, Zygoascus hellenicus and Saccharomyces cerevisiae were isolated from the spoiled products. The data provided a yeast control panel that was used successfully to identify unknown yeasts in spoiled products from this factory using polymerase chain reaction-restriction length polymorphism (PCR-RFLP) comparative analysis.

Pulsed ultraviolet light is a potential postprocessing decontamination method which is able to reduce pathogens on solid food surfaces. Cheese surfaces may become easily contaminated with pathogens due to improper handling or contact with unhygienic surfaces during or after processing. In this study, the effects of pulsed ultraviolet light on Staphylococcus aureus and Escherichia coli O157:H7 on fresh kashar cheese were investigated. Pulsed ultraviolet light was applied to kashar cheese for different times (5, 15, 30, 45, 60 s) at 5, 8, and 13 cm from the quartz window in a pulsed ultraviolet light system. Based on the inactivation level, time, and visual evaluation, the most favorable treatment was determined as the 45 s–13 cm treatment (∼44 J/cm²). This treatment yielded about 1.62 and 3.02 log₁₀ reductions (cfu/cm²) for S. aureus and E. coli O157:H7, respectively, while did not alter (p>0.05) the pH, lipid oxidation, and moisture content of kashar cheese, except the color parameters. When 0.5 cm thick kashar cheese was treated with pulsed ultraviolet light at a distance of 5 cm from the quartz window, the highest energy transmittance was found to be about 9.16%. These findings demonstrate that pulsed ultraviolet light has the potential for postprocessing decontamination of semi-hard cheese surfaces.

The co-culture growth of Staphylococcus aureus, Escherichia coli and lactic acid bacteria starter culture in milk was quantitatively evaluated and modelled with a set of coupled differential equations originally proposed by Baranyi and Roberts and by Gimenez and Dalgaard (BR–GD model). The lactic acid bacteria starter culture showed the ability to induce an early stationary phase of both E. coli and S. aureus populations at different combination of temperature (ranging from 12 to 37 ℃) and lactic acid bacteria inocula (from approx. 10³ to 10⁶ CFU/ml). First, the prediction ability was performed only with parameters estimated from individual growth curves of E. coli, S. aureus and the lactic acid bacteria in milk (Dataset 1, 21 experiments). Subsequently, the model was extended with the average competition coefficients (E-BR–GD model) that represented quantitative relations among the populations. The prediction ability of this model was validated with the second dataset consisting of seven experiments. Results and also their statistical indices (accuracy and bias factors) showed that the E-BR–GD model improved growth prediction of all involved populations. Thus, the total root mean square error decreased from 0.457, 0.840 and 0.322 log CFU/ml (BR–GD model) to 0.290, 0.245 and 0.333 log CFU/ml (E-BR–GD) for S. aureus, E. coli and lactic acid bacteria, respectively. This approach in growth prediction of multiple competing microbial populations can be used in assessment of S. aureus and E. coli exposure from raw milk cheeses consumption and contribute to decision making in prevention of staphylococcal enterotoxin production.

Herbal infusions are a new emerging trend among consumers, appearing in the market in many different forms. Due to intense competition, the commercial success of herbal infusions largely depends on flavour. The identification of the best combinations of steeping time and water temperature for the preparation of Aloysia triphylla infusions using a central composite design and response surface methodology was performed. The procedure aimed to maximize its antioxidant activity, phenolic and aromatic compounds, and consumers’ liking of the infusions. The antioxidant activity and phenolic content were evaluated using the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical cation) method and the Folin–Ciocalteu procedure. The analysis of aromatic compounds was performed based on the method of terpenic compounds. Sensory evaluation encompassed overall liking using a 9-point hedonic scale. Antioxidant activity and extraction of most phenolic compounds was higher for longer steeping times and higher temperatures, with some presenting a contrasting effect due to degradation at higher temperatures for longer steeping times. Results for terpenic compounds showed similar contrasting patterns. Based on the quadratic response surface, it was possible to predict the maximum overall liking for lemon verbena infusions prepared by brewing for 6 min at 96 ℃. Under such conditions, extraction of bioactive compounds was kept at a high level, close to the maximum attainable, while reducing the extraction of bitter compounds. These results are considered of great importance for the development of premium infusions from organic lemon verbena leaves.

This research explores the cell wall composition and polyphenol oxidase activity of two pawpaw (Asimina triloba) fruit varieties, Susquehanna and Green River Belle, that were subjected to high pressure processing and 45 days of refrigerated storage. We hypothesize that high pressure processing may inhibit enzymatic action responsible for pawpaw's deleterious postharvest tissue softening and browning. Glycome profiling uses mAb groupings that recognize 19 groups of glycan epitopes present in most major classes of cell wall glycans and was used to determine cell wall composition. Results show that both varieties have typical type I primary cell walls of flowering dicots. However, differences in the fine cell wall structure between the varieties can be inferred and the varieties behaved differently during refrigerated storage, likely indicating of a difference in cell wall-modifying enzymes present in the primary cell walls. High pressure processing treatment does not seem to be effective at eliminating polyphenol oxidase activity.