Physical,Sensory and Microbiological Properties of Wheat-Fermented Unripe Plantain Flour

The physical, sensory and microbiological properties of wheat-fermented unripe plantain composite flour bread were studied. Mature unripe plantain was peeled, sliced, steam blanched, dried and milled into flour. The flour was made into a slurry (10 g of flour/3 ml of water) and allowed to ferment for 24 h. It was then dried, pounded and sieved through 0.25 mm sieve. The fermented unripe plantain flour was then blended with wheat flour in the ratios of (wheat:fermented unripe plantain) 100:0; 90:10; 80:20; 70:30; and 60:40. Bread was produced from the flour blends using the straight dough method. Loaf weight and volume decreased significantly (p < 0.05) with increasing levels of plantain flour inclusion. Sensory evaluation of the flour samples revealed significant differences in the ratings for crumb colour and texture between 100% wheat flour (100:0) and 60% wheat-40% fermented unripe plantain flour (60:40) bread but no significant difference was observed between all bread samples with respect to crust colour, taste, aroma and overall acceptability. The sensory scores showed that all the bread samples were acceptable. Microbiological analysis (total viable count) revealed that all the bread samples were free of microorganisms for up to four days after production.     

Effect of Honey as Partial Sugar Substitute on Pasting Properties,Consumer Preference and Shelf Stability of Cassava-Wheat Composite Bread

The effect of partial substitution of sugar with liquid honey on the pasting properties of cooked dough made from cassava-wheat composite (10:90) flour as well as the sensory preference and shelf stability of its bread was investigated. Sucrose (S) in the bread recipe formulation was substituted with honey (H) at levels 0, 10, 20, 30, 40 and 50%, respectively to give 6 treatments, namely 0H:100S, 10H:90S, 20H:80S, 30H:70S, 40H:60S and 50H:50S. Amylograph pasting properties of the dried crumbs were determined using standard analytical procedures. Fresh bread samples were subjected to sensory evaluation and fungal count during storage (6 days). Peak, final and setback viscosities of bread crumb decreased (32.29 to 25.33, 58.54 to 43.00 and 30.96 to 23.66 RVU), respectively as the level of honey inclusion increased. Honey substitution levels used did not significantly (p > 0.05) affect aroma and texture of the bread samples but composite bread with 20% level of honey substitution was most preferred in terms of colour while composite bread with 30% level of honey substitution was most acceptable in terms of taste and overall acceptability. Fungal count in stored honey-cassava-wheat bread varied significantly (p < 0.05) from 0.6 to 4.0 × 10², 1.0 to 6.9 × 10², 2.2 to 57.0 × 10², 32.0 to 135.7 × 10², 34.0 to 140.0 × 10² and 42.0 to 159.3 × 10²) cfu/ml from day 1 to day 6, respectively. From the study, it was concluded that substitution of sugar with honey in dough formulations significantly (p < 0.05) affects dough pasting properties, improves acceptability of the composite bread and reduces staling rate.     

Investigation on the rheological properties of agar gels and their role on aroma release in agar/limonene solid emulsions

A lipophilic aroma widely used in the food field, R-(+)-limonene, was entrapped in a solid emulsion in absence of emulsifiers using agar gel as encapsulating medium. The perception of the flavour release was evaluated by means of an electronic nose. The relation between structural organization of the agar gels and flavour release and perception was studied. Different viscoelastic properties of the continuous phase of the solid emulsion were achieved by varying the gelling polysaccharide concentration from 0.2% up to 1% (w/v) and the consequent aroma trapping effect was correlated with the perception of the flavour release from the solid emulsion during aging up to 15 days storage. Release phenomena were finally accelerated by increasing temperature of the gel from 30 to 77 °C. Structure assessment of the gelled phase take place within 24 h from the gel setting time and during this transient period most of the aroma release happens.     

Change regime of aroma active compounds in response to pulsed electric field treatment time,sour cherry juice apricot and peach nectars,and physical and sensory properties

Regime (direction, amount, rate, and pattern) of change in aroma active compounds was quantified as a function of four pulsed electric field (PEF) treatment times, three fruits, and 10 physical and eight sensory properties using the best-fit multiple linear regression (MLR) models. The PEF treatment times did not deteriorate 94% of the sensory properties and 70% of the physical properties and significantly change 57% of a total of 73 aroma active compounds detected for sour cherry juice, and apricot and peach nectars. The best performing MLR models belonged to 1-methyl-4-prop-1-en-2-ylcyclohexene as a function of fruit type, treatment time, and titratable acidity (= 49 mg/L; R_adj² = 95.7%; R_cv² = 94.9%) and to 2-[(2S,5S)-5-ethenyl-5-methyloxolan-2-yl]propan-2-ol as a function of fruit type, and treatment time (SE = 157 mg/L; R_adj² = 98.2%; R_cv² = 98.0%), respectively (n = 48; p < 0.001).Industrial relevancePulsed electric field (PEF) is one of the leading nonthermal food technologies especiallyfor processing of high acid low viscosity foods with satisfactory quality and microbial inactivation. It was shown in this study that PEF with different treatment times can successfully be applied in the pasteurization of sour cherry juice, and apricot and peach nectars with minimum loss of aroma active compounds and sensory and physical properties. Both PEF processing conditions and results can be used as a guide to determine PEF processing parameters for industrial scale processing of juices/nectars.     

Sensory changes during bottle storage of Spanish red wines under different initial oxygen doses

Sixteen commercial Spanish red wines selected to cover a wide range of sensory properties were stored at 25 °C for 6 months in air-tight containers under different oxygen doses (0–30 mg L^− 1) mimicking real and extreme bottling situations. The 16 initial samples (before storage) and the 80 stored samples (16 wines × 5 oxygen doses) were submitted to sensory analysis. Sensory changes related to post-bottling storage and initial oxygen dose were evaluated by means of discriminant and characterisation sensory strategies.Significant increases in black fruits, dried fruits, woody, lactic and stronger increases in cooked vegetables and spicy notes reveal a general pattern of aroma evolution. Remarkable departures to this general pattern have been observed, which can be related to the initial sensory properties of the wines and to their basic polyphenolic composition. The effect of post-bottling storage in bitterness is wine dependent, while global decreases in both global intensity and persistence evaluated in mouth are observed. Discrete increases in astringency are observed for wines with the lowest initial astringent scores. Important sensory interactions between aroma attributes (herbal and spicy) and bitterness and between roasted and astringency perception are shown. Little impact of the initial oxygen dose in the in-mouth sensory properties is reported. These results are relevant for wine experts in that they help understanding the evolution of wine sensory properties in the bottling stage. This study may help them to develop strategies for managing this winemaking stage with objective criteria.     

Physical,Chemical and Sensory Properties of Baked Products from Blends of Wheat and African Yam Bean (Sphenostylis stenocarpa) Water-Extractable Proteins

Blends of wheat flour (WF) and African yam bean water-extractable proteins (AYBWEP) were processed into bread and cookies in the following ratios: 100: 0; 95: 5; 90: 10; 85: 15; 80: 20. The proximate composition, physical, chemical properties and sensory properties of bread and cookies samples from the blends were determined. Breads and cookies produced from the resultant blends were significantly higher (p < 0.05) in protein (16.39% – 18.36%) than the control (11.80% – 12.58%). Carbohydrate content decreased from 60.74% with addition of AYBWEP to 52.81% following 20% substitution. The pH of bread samples prepared from whole wheat flour and blends of wheat flour and AYBWEP were significantly different (p < 0.05) while bulk density and specific volume were not significantly different (p > 0.05). The pH of bread samples and cookies decreased with increase in the proportion of the AYBWEP blend from 5% to 20%. The highest specific volume (3.70 ml/g) was observed in bread samples prepared from the control 100: 0 blends while the 80:20 blends had the lowest specific volume (3.10 ml/g). There was no significant difference (p > 0.05) in the bulk density and thickness of the cookies. The cookies prepared using 80: 20 blends had the higher diameter (22.53 cm) and spread factor (54.03 cm) compared to the control. Generally, acceptability of the bread and cookies decreased with higher ratios of AYBWEP inclusion. The sensory acceptability scores showed the best AYBWEP substitution level for making bread and cookies was 5% and 10% of the AYBWEP respectively. The results are discussed in the context of the growing importance of promoting the processing and utilization of lesser known local crops in baked products.enrichment.     

Moisture diffusivity coefficient estimation in solid food by inversion of a numerical model

Knowledge of moisture diffusivity coefficients of water in food is a very important physical parameter for design, modelling and simulation of different food plants and related processes such as baking, drying and ripening. Unfortunately specific moisture diffusivity values are not easily found in literature, particularly for processed foods. The aim of this study was to develop a method, based on the inversion of finite element models, to estimate the moisture diffusivity in different solid food products. An example on salami, biscuit and flat bread is shown. The research work was divided in three phases: experimental determination of the moisture concentration versus time in various food products stored in water saturated atmosphere; development of a numerical model of water transfer inside the food product for the numerical determination of moisture content versus time and parameter estimation of moisture diffusivity, by minimizing the distance between numerical model and experimental results using the Levenberg–Marquardt algorithm.The estimated moisture diffusivity coefficients resemble those reported in literature for almost similar products (3.857E − 12, 6.804E − 11 and 1.792E − 12 m²/s for salami, biscuits and flat bread respectively). The obtained values were then used for solving direct models, in unsteady conditions, showing a good agreement with experimental data.The method may be used on different food materials and it is possible to hypothesize an integrated automatic instrument, useful both for laboratory and industrial purposes.     

Sensory profile,acceptability, and their relationship for diabetic/reduced calorie chocolates

The purpose of this study was to determine the sensory properties and acceptability of lab developed prototypes of conventional, diabetic (with no sugar), and diabetic/reduced calorie milk chocolates (no sugar and 25% calorie reduction) with high-intensity sweeteners, sucralose and stevioside, and partial fat replacement with whey protein concentrate (WPC). PLS was performed in order to relate sensory properties and consumer acceptability and to determine drivers of liking and disliking. There was no difference between conventional, diabetic and diabetic/reduced calorie milk chocolates for brightness, cocoa aroma, cocoa butter aroma, and cocoa flavor (p > 0.05). Acceptability was higher for sucrose substitution by sucralose than by stevioside and partial fat replacement reduced acceptability of flavor even more (p ? 0.05). Crucial attributes which determine consumer acceptability in samples are sweet aroma, melting rate, and sweetness, whereas bitterness, bitter aftertaste, adherence, and sandiness were drivers of disliking.     

Modification of perceived beer bitterness intensity,character and temporal profile by hop aroma extract

The effect of hop aroma on perceived bitterness intensity, character and temporal profile of beer was investigated. A hop aroma extract was added at 3 levels (0, 245, 490 mg/L) to beers at low, medium and high bitterness. Beers were evaluated for perceived bitterness intensity, harshness, roundedness and linger by a trained panel using a rank-rating technique at each bitterness level, with and without nose clips. The use of nose clips enabled the olfactory aspect to be decoupled from taste and mouthfeel aspects of bitterness perception. Results showed significant modification of perceived bitterness in beer by hop aroma depending on the inherent level of bitterness. These modifications were mainly driven by olfaction – in an example of taste-aroma interactions, as well as certain tactile sensations elicited by the hop aroma extract in the oral cavity. At low bitterness, beers with hop aroma added were perceived as more bitter, and of ‘rounded’ bitterness character relative to those without hop aroma. When judges used nose clips, this effect was completely eliminated but the sample was perceived to have a ‘harsh’ bitterness character. Conversely, at high bitterness, even when nose clips were used, judges still perceived beers containing hop aroma to be more bitter. These increases in bitterness perception with nose clips indicates the stimulating of other receptors, e.g. trigeminal receptors by hop aroma extract, which in tandem with the high bitterness, cause perceptual interactions enhancing bitterness intensity and also affecting bitterness character. Bitterness character attributes such as ‘round’ and ‘harsh’ were found to significantly depend on bitterness and aroma levels, with the second level of aroma addition (245 mg/L) giving a ‘rounded’ bitterness in low bitterness beers but ‘harsh’ bitterness in high bitterness beers. The impact of aroma on temporal bitterness was also confirmed with time-intensity measurements, and found to be mostly significant at the highest level of hop aroma addition (490 mg/L) in low bitterness beers. These findings represent a significant step forward in terms of understanding bitterness flavour perception and the wider impact of hop compounds on sensory perception.     

The consumer acceptance of novel vegetable-enriched bread products as a potential vehicle to increase vegetable consumption

Currently UK fruit and vegetable intakes are below recommendations. Bread is a staple food consumed by approximately 95% of adults in western countries. In addition, bread provides an ideal matrix by which functionality can be delivered to the consumer in an accepted and convenient food. Therefore, enriching bread with vegetables may be an effective strategy to increase vegetable consumption. This study evaluated bread enriched with red beetroot, carrot with coriander, red pepper with tomato or white beetroot (40 g vegetable per 100 g) compared to white control bread (0 g vegetable) for consumer acceptance. Consumers (n = 120) rated their liking of the breads overall, as well as their liking of appearance, flavour and texture using nine-point hedonic scales. Product replacement and purchase intent of the breads were rated using five-point scales. The effect of providing consumers with health information about the breads was also evaluated. There were significant differences in overall liking (P < 0.0001), as well as liking of appearance (P < 0.0001), flavour (P = 0.0002) and texture (P = 0.04), between the breads. However, the significant differences resulted from the red beetroot bread which was significantly (P < 0.05) less liked compared to control bread. There were no significant differences in overall liking between any of the other vegetable-enriched breads compared with the control bread (no vegetable inclusion). The provision of health information about the breads did not increase consumer liking of the vegetable-enriched breads. In conclusion, this study demonstrated that vegetable-enriched bread appeared to be an acceptable strategy to increase vegetable intake, however, liking depended on vegetable type.     

School meal acceptance depends on the dish,student, and context

Students (n = 127) from grades 3, 6, and 8 (8–15-year-old) evaluated 13 school meals with special attention to main dishes. Hedonic ratings (1 = really bad, 7 = really good) of 1109 meals, perceived hunger prior to eating, and aspects of the eating context were rated. Attitudes to school meals and food neophobia were measured. Considerable differences were observed in responses to main dishes, soups being better accepted than casseroles or dishes served with starches. A semi-trained laboratory panel (n = 17) characterized the best liked main dishes as being recognizable by appearance, odor and flavor, and bright and colorful, while the least liked dishes were described as having fatty mouth feel and cheesy odor and flavor. Hedonic ratings of main dishes were highly correlated with overall meal ratings. The 3rd graders rated the main dishes higher than 6th and 8th graders, who perceived them as too low in spiciness and not hot enough when served. Typically, 3rd grade boys rated the meals most positively and 6th grade boys most negatively. Attitudes to school meals were more positive in 3rd graders than in higher-grade students. In regression analysis explaining 29.7% of variation, hedonic ratings of the meals were positively predicted by attitudes to school food, perceived hunger, and appropriate queuing in the canteen, and negatively predicted by food neophobia and being a 6th or 8th grader. In conclusion, sensory characteristics of main dishes greatly affect the popularity of school meals; and means to impact the negative attitude to school food in teenage would be of great use.     

Effect of Lactobacillus brevis-based bioingredient and bran on microbiological,physico-chemical and textural quality of yeast-leavened bread during storage

The effects of wheat bran and of a Lactobacillus brevis-based bioingredient (LbBio), obtained after growth in flour-based medium, on quality of yeast-leavened wheat bread (WWB) were investigated. Bran was used in bread formulation by substituting a part (20 g/100 g) of white wheat flour (WBB), while LbBio was used instead of the water content (WWB + LbBio and WBB + LbBio). The use of LbBio in WWB resulted in the biological acidification of the dough due to lactic, phenyllactic and OH-phenyllactic acid contents determining a high fermentation quotient value and an improved bread texture and microbiological quality. Conversely, wheat bran reduced the specific volume and crumb hardness during storage at 25 °C, and affected the antibacterial ability of LbBio during 30 °C storage. Our findings demonstrated that LbBio counteracted the negative effects of bran and allowed to obtain an enriched fibre bread with specific volume and soft crumb comparable to bread without bran.Industrial relevanceBread is a perishable food with a short microbiological and physico-chemical shelf-life. The main microbiological alteration occurring into few days after baking is the “rope spoilage” caused by spore-forming bacteria originating from raw materials. This phenomenon, often misinterpreted as a sign of unsuccessful dough leavening and not visible from outside, is more common under industrial production conditions during the hot season causing large economic losses in the warm climates of Mediterranean countries, Africa and Australia. The use of sourdough often controls this alteration even if the industrial application of this traditional process is limited by the long leavening times. In this study, an innovative procedure for the preparation of yeast-leavened bread comprising the addition of a fermentation product from Lactobacillus brevis grown in a flour-based medium has been applied. The resulting fermentation product (LbBio bioingredient) acts as a sourdough acidifying the dough and improving the textural, physico-chemical and microbiological properties of the resulting bread. The application of bioingredient LbBio could represent an innovative strategy in industrial bread production to obtain acidified yeast-leavened products, thus, preventing the ropy spoilage and reducing the negative effects of bran addition.     

Reducing SO2 in fresh pork burgers by adding chitosan

The use of 0.02 or 0.05% chitosan is proposed to reduce from 450 to 150 mg kg^− 1 the SO₂ required to preserve pork burgers aerobically packed and stored at 2 °C for up to 21 days under retail display conditions. The effects of chitosan and/or sulfite addition and the storage time were determined in fresh (color deterioration, lipid oxidation, pH, total viable counts, Escherichia coli and coliforms, Salmonella, appearance and odor) and cooked (appearance, odor, flavor and texture) burgers. The addition of either 0.02 or 0.05% chitosan was not detected by sensory analysis, and extended the shelf life of low-SO₂ burgers from 7 to 14 days. Chitosan enhanced the preservative effects of sulfite at a low dose, acting on the main causes of meat deterioration (bacterial spoilage, color stability and lipid oxidation), and provided good sensory properties to fresh and cooked pork burgers.     

Sensory changes in extruded oat stored under different packaging,light and temperature conditions

The sensory quality of extruded oat, stored in light and darkness in packages with different oxygen transmission rates (including the use of an oxygen absorber), was evaluated after 3 months of storage at 38 °C and 10 months of storage at 23 °C. To reduce the costly and time consuming shelf life and packaging evaluation, the possibility of reducing the number of sensory attributes to be analyzed and to accelerate shelf life testing was studied.The intensity of oat odor, paint odor and crispiness were found to describe the main differences among the samples. By increasing the temperature from 23 to 38 °C for samples stored in darkness, packaging evaluation tests for extruded oat might be performed in approximately one third of the time. Changes in headspace oxygen concentration in the packages due to oxygen consumption were in agreement with the sensory changes in the oat.     

Dynamics of the loss and emergence of volatile compounds during the concentration of cashew apple juice (Anacardium occidentale L.) and the impact on juice sensory quality

Concentrating cashew apple juice alters the beverage aroma and flavor, compromising consumer acceptability of the concentrated beverage. To understand the mechanisms involved in these changes, this research characterized the dynamics of the loss and emergence of volatile compounds during cashew apple juice concentration, reporting their impact on beverage sensory quality. Fresh cashew apple juice (10.3°Brix) was concentrated in a thermal-siphon type evaporator operating in a closed system. Five samples were taken throughout the concentration process with the following soluble solids contents: 11.8°Brix, 14.9°Brix, 20.2°Brix, 29.6°Brix and 42.1°Brix. Trained judges rated the aroma note intensities, described as “fresh cashew apple” and “cooked” as perceived in the fresh and concentrated beverages. The headspace volatiles of the six samples were identified and quantified by GC–MS. The results indicated the esters as the major component in the fresh juice (226.46 μg kg^− 1) representing 45.0% of the total mass of volatiles, followed by the terpenes (118.98 μg kg^− 1), acids (45.23 μg kg^− 1), aldehydes (39.10 μg kg^− 1), alcohols (18.91 μg kg^− 1), lactones (19.15 μg kg^− 1), hydrocarbons (18.02 μg kg^− 1) and ketones (11.05 μg kg^− 1). Predictive statistical models (R² > 0.956, p ≤ 0.002) revealed that on reaching 14.9°Brix, the ester concentration declined more than 90%, the terpene content almost 100%, alcohols 85%, aldehydes 80% and hydrocarbons 90%. At 14.9°Brix, the intensity of “fresh cashew apple” aroma still predominated in the juice, but the panelists detected the presence of a weak “cooked” aroma. Concentration of the beverage to 20.2°Brix or above expressively increased the cooked aroma intensity and the concentration of hydrocarbons, alcohols and some aldehydes usually associated with off-flavors such as pentanal and decanal. This raises the possibility that some of these compounds might have been formed during juice processing. Juice with better sensory quality could possibly be obtained by concentrating the beverage to levels below 20.2°Brix, recovering the esters that evaporated off the juice until ~ 15°Brix is reached, and re-adding them to the juice concentrated.     

Improved keeping quality of minimally fresh processed celery sticks by modified atmosphere packaging

Recommended storage conditions of green celery sticks are 4 °C for 10 days, but there are no reports about optimal modified atmosphere packaging (MAP) conditions to preserve them longer. The objective of this research was to describe the gas composition of MAP generated by two polymeric films and its effects on chemical, sensorial and microbial quality, and physiological disorders of celery sticks stored at 4 °C for 15 days. Green sticks of 15-cm length of ‘Trinova’ cv. were placed in hermetically sealed plastic bags: low-density polyethylene, oriented polypropylene (OPP) and polyethylene-perforated bags as control (air). The O₂ and CO₂ concentrations, soluble solid content, pH, titratable acidity, colour, sensorial quality and sugar and organic acids contents were monitored. Compared to the control, both MAP treatments improved the sensory quality, avoided the loss of green colour, decreased the development of pithiness and retarded the growth of microorganisms. In any treatment neither off-odours nor off-flavours were detected. After 15 days at 4 °C within the OPP bags a steady-state atmosphere of 6 kPa O₂+7 kPa CO₂ was reached and celery sticks stored under these bags showed the best quality.     

Bread Making Potential of Composite Flour of Wheat-Acha (Digitaria exilis staph) Enriched with Cowpea (Vigna unguiculata L. walp) Flour

Bread-making potentials of composite flours containing 90% wheat and 10% acha enriched with 0-15% cowpea flour were investigated. Proximate composition and functional properties of the blends were studied using AOAC standard methods. Bread loaves were prepared from the blends using the straight dough method and evaluated for loaf height, loaf volume, loaf weight and sensory characteristics. Crude protein, crude fat, crude fibre and ash contents increased significantly (p < 0.05) with increase in level of cowpea flour addition, but moisture content was not significantly (p > 0.05) different among the blends. Functional properties, with exception of bulk density and swelling capacity, were significantly (p < 0.05) different among the blends. Average loaf height and loaf volume decreased significantly (p < 0.05) with increased cowpea flour but loaf weight showed opposite trend with significant (p < 0.05) differences as cowpea flour increased. However, the addition of cowpea flour significantly (p < 0.05) decreased the loaf specific volume but all enriched samples were not significantly (p > 0.05) different. Bread samples from composited blends were rated lower than bread from all wheat bread. Bread loaves from enriched composite flour with up to 10% cowpea flour were acceptable to the panelists.     

Use of applied air pressure to improve the baking properties of whey protein isolates in angel food cakes

Whey protein isolate (WPI) possesses limited application in angel food cake baking compared to liquid egg white (LEW). This study was conducted to determine whether applying air pressure in the oven during baking would improve the baking properties of WPI in angel food cakes. A special oven was designed for baking at oven air pressures up to 1.5 bar. Control angel food cakes were formulated with LEW (100/0) as its protein source and WPI-containing cakes were formulated with a mixture of 75 mL/100 mL LEW and 25 mL/100 mL WPI solution (75/25) or a mixture of 50 mL/100 mL LEW and 50 mL/100 mL WPI solution (50/50). Cakes were baked at atmospheric air pressure (AP) and at constant applied air pressure (CAP) or variable applied air pressure vs. baking time (VAP) to prevent overexpansion and collapse of WPI-containing cake batter. Cakes 75/25 and 50/50 baked at VAP exhibited improved physical, textural and sensory properties compared to those baked at AP or CAP conditions. Cakes 75/25 baked at VAP compared well with control angel food cakes baked at AP. Although 50/50 cakes baked at VAP were improved slightly over those baked at AP, none of them exhibited satisfactory properties. Therefore, additional research is needed to optimize baking conditions for cakes formulated with less than 75 mL/100 mL LEW.