Persistence of oral coatings of CMC and starch-based custard desserts

Food coatings that remain after swallowing starch-based or CMC-based custard desserts were investigated for 19 subjects. Foods were orally processed for 5 s using a pre-defined protocol, after which the food was swallowed. The remaining food coating was assessed sensorially as well as instrumentally using turbidity of rinse water. The instrumental and sensory results indicated a gradual decline of food coatings over intervals up to 180–270 s. Decline rates of coatings of individual subjects related significantly to their decline rates in perceived fattiness.     

Interactions between flavour release and rheological properties in model custard desserts: Effect of starch concentration and milk fat

The influence of the concentration of various reagents and of the storage time on the flavour release of custard desserts was evaluated by headspace solid-phase microextraction and supported by rheological measurements. The presence of milk fat induced a significant decrease of the headspace concentration of flavour compounds, mainly due to hydrophobic matrix–flavour interactions. An elevated starch concentration enhanced the strength of the custard gels considerably. However, the increasing starch concentration resulted in an increased flavour release at low flavour concentrations, while a tendency to flavour retention was noted at higher flavour concentrations. During storage time, a denser network was formed as shown by rheological measurements, but no significant difference in flavour release was noted upon storage (three days). These results show that the complex interactions between flavour compounds and the food matrix in a model custard are difficult to predict and have to be carefully evaluated by a combination of rheological parameters and physicochemical interactions.     

Clean label starches as thickeners in white sauces. Shearing, heating and freeze/thaw stability

The linear viscoelastic properties and syneresis of freshly prepared and freeze/thawed white sauces prepared with different native starches (corn, waxy corn, potato and rice) at different shearing speeds were studied. Viscosity changes during processing were also measured using a starch pasting cell attached to a rheometer. The freeze/thaw cycle produced a significant increase in the viscous and elastic modulus and the appearance of syneresis in the corn and potato starch sauces, while the waxy corn and rice starch sauces were only slightly affected. Syneresis was significantly reduced upon subsequent heating. Greater shearing speed produced a significant decrease in viscoelasticity. Viscosity profiles revealed that the increase in shearing speed decreased the starch gelatinization temperature and swelling capacity and increased starch breakdown.     

Effect of cooking time and ingredients on the performance of different starches in white sauces

The effect of white sauce ingredients and increased cooking time at 90 °C on the degree of gelatinization of corn, waxy corn, rice, potato and modified waxy corn starches was studied. The changes in pasting properties, linear viscoelastic properties, and microstructure were determined. In all the native starches in water, a longer cooking time at 90 °C caused greater starch granule swelling and more leaching of solubilized starch polymers into the intergranular space. These effects were more noticeable in the waxy corn and potato starches. The potato starch was the most affected, with complete disruption of the starch granules after 300 s at 90 °C. The microstructural changes which transformed a system characterized by starch granules dispersed in a continuous phase (amylose/amylopectin matrix) into a system with an increase in the continuous phase and a decrease in starch granules were associated with a decrease in system viscoelasticity. The elastic moduli were higher in the sauce than in the starch in water system. However, with the exception of potato starch, the white sauce showed lower viscoelasticity than the starch in water system. The white sauce ingredients decreased the effect of cooking time on the starch gelatinization process, particularly in potato starch.     

Structural stability of white sauces prepared with different types of fats and thawed in a microwave oven

This paper describes the microstructure and dielectric properties of white sauces prepared with different fats (sunflower oil, olive oil, soy oil, and butter) and agitation speeds (350, 1100 and 3250 rpm). The structural stability of sauces during thawing using conventional oven (CO) and microwave oven (MO) are studied. The results showed that, for fresh samples (not subjected to the freeze-thaw cycle) an increase in agitation speed during elaboration from 350 to 1100 rpm caused a significant decrease (p < 0.05) in the fat globules area - regardless of the type of fat used; in the samples with sunflower and olive oils, a significant increase (p < 0.05) in the fat globules circularity and dielectric properties (dielectric constant and loss factor) was also produced. The thawing method used did not significantly (p > 0.05) affect fat globule size and shape, regardless of the agitation speed and type of fat. Sauces that were stable during the freeze-thaw cycle were obtained using speeds of 1100 and 3250 rpm.     

Oxidative stability of camelina oil in salad dressings,mayonnaises and during frying

Oxidative stability of omega‐3 rich camelina oil in food products and during frying was evaluated and compared with sunflower oil. Camelina oil‐based salad dressings were of similar oxidative stability to those prepared with sunflower oil, as indicated by predominantly insignificant (P > 0.05) differences in peroxide values (PV), ρ‐anisidine values (AV), total oxidation values (TOTOX), conjugated diene levels (CD) and conjugated triene levels (CT). However, thiobarbituric acid reactive substances (TBARS) were significantly higher (P < 0.05) for camelina oil and salad dressings throughout storage. Camelina and sunflower oils, alone and in salad dressings or mayonnaises, were acceptable to a sensory analysis panel with slightly lower scores for camelina oil. PV, AV and TOTOX values were similar for camelina and sunflower oil during deep frying but while PVs remained low (<10 meq kg^?1), AV and TOTOX values increased quickly. TBARS values were significantly higher in deep‐frying camelina oil and ‘fishy’ odours were observed.     

Gelled vegetable desserts containing pea protein, κ-carrageenan and starch

Due to recent animal diseases, cholesterol intake worries and strong demand for healthy food, there is a greater pressure for the direct consumption of vegetable proteins in food products. In this work, the objective is to develop alternative of strictly vegetable origin desserts based on gelled systems with required physical structure and perceived texture. For this reason, it is important to control the properties of the biopolymer mixtures and understand the phase separation behaviour under different physicochemical conditions. The firmness and storage modulus of different formulations of pea protein/κ-carrageenan/starch systems processed and cooled at different conditions are compared with those parameters obtained for commercial products. Formulation and thermal conditions were determined to influence the texture and storage modulus of the mixed systems. Confocal microscopic images showed that phase separation between pea protein and κ-carrageenan takes place, leading to the formation of two network systems. The binding of water effect, of the starch swollen granules, promotes the concentration of pea protein and κ-carrageenan, reinforcing the gel structure.     

Uses for dairy ingredients in ice cream and other frozen desserts

The use of milk products in ice cream in the UK is governed by legal requirements and the way in which these are interpreted. Sources of fat, and of milk-solids-not-fat in concentrated form, are considered. After basic legal requirements have been met. whey powders or concentrates can provide additional protein. Lactose and whey syrups can also be used as sweeteners. Other milk-based desserts such as sherbets and mousse have no legal compositional requirements, so milk products can be used in their formulation in different ways.     

Improving effect of xanthan and locust bean gums on the freeze-thaw stability of white sauces made with different native starches

The effect of adding xanthan gum and locust bean gum at low concentrations (0.15% w/w) on the freeze/thaw stability of white sauces prepared with native starches from four different sources (corn, waxy corn, potato, and rice) was investigated. Linear viscoelastic properties were taken as structural indicators and these and syneresis as indicators of the freeze/thaw stability of the sauces. The pasting properties of the starch in the sauce system were also studied. Both hydrocolloids reduced the structural changes occurring after thawing, xanthan gum being more effective than locust bean gum. In corn and potato sauces, the most affected by the freeze/thaw cycle, the appearance of syneresis and the increase in viscoelastic functions were significantly reduced by both hydrocolloids. In general, the addition of hydrocolloids affected peak, hot peak and cold peak viscosities and reduced relative total setback. The results regarding the possible effects of hydrocolloid addition to white sauce systems are discussed in molecular terms.     

Fatty acid composition of backfat in large white pigs selected for low backfat thickness

Samples of midback fat were taken from 157 Large White boars and analysed for fatty acid composition and melting point of lipid. Seventy-seven boars were from a line showing fast efficient growth and low backfat depth (selection line) and 80 from a random-mated control line. All were performance-tested from 27 to 87 kg liveweight on ad libitum feeding.

Selection line pigs required 6 % less feed per kilogramme liveweight gain and had thinner backfat at each point of measurement (16–27 %) than the controls but there was no line difference in daily liveweight gain. Selection line pigs had ‘eye muscles’ which were slightly paler and had a greater drip loss than the controls.

The fatty acid composition and melting point of the lipid extracted from backfat was similar between the lines except that the concentration of linoleic acid (C18:2) in both inner and outer layers was some 14% higher in the selection line. There were significant negative correlations between the concentration of C18:2 and the various backfat measurements. Positive correlations were found between some backfat measurements and the concentration of stearic acid (C18:0), particularly in the selection line.

Variation in melting point in both layers was more strongly related to variation in the concentration of C18:0 than to that of any other fatty acid.     

Fatty acid profiles,meat quality,and sensory attributes of organic versus conventional dairy beef steers

Meat from Holstein and crossbred organic and conventional dairy steers were evaluated and compared for fatty acid profiles, meat quality, sensory attributes, and consumer acceptance. Bull calves (n = 49) were randomly assigned to 1 of 3 replicated groups: conventional (CONV), organic (ORG, pasture + concentrate), or grass-fed organic (GRS) and were born at the University of Minnesota West Central Research and Outreach Center (Morris, MN) between March and May 2011. The CONV steers (n = 16) were fed a diet that contained 80% concentrate and 20% forage, and ORG steers (n = 16) were fed a diet of organic corn, organic corn silage, and organic protein supplement. Furthermore, ORG steers consumed at least 30% of diet dry matter of high-quality organic pasture during the grazing season. The GRS steers (n = 17) consumed 100% forage from pasture during the grazing season and high-quality hay or hay silage during the nongrazing season. The ORG steers had fat that was greater in oleic acid (C18:1) than the GRS and CONV steers (47.1, 36.1, and 39.9%, respectively). The GRS steers (21.9%) were lower for monounsaturated fat than the ORG (42.1%) and CONV (40.4%) steers. Furthermore, the GRS steers tended to have greater n-3 fat and had lower n-6 fat than the ORG and CONV steers. Consequently, the GRS (1.4%) steers had a lower n-6-to-n-3 fat ratio than the ORG (12.9%) and CONV (10.0%) steers. The GRS (2.6 kg) steers had steaks that were not different for Warner-Bratzler shear force than ORG (2.3 kg) steaks; however, the GRS steaks tended to have greater shear force than the CONV (2.0 kg) steaks. The 3 steer group had steaks that were not different for color brightness (L*; 0 = black and 100 = white) and yellowness/blueness (b*; positive values = yellow and negative values = blue) values; however, the GRS (10.5) steaks had lower redness/greenness (a*; positive values = red and negative values = green) values than CONV (14.5) steaks. For sensory attributes (0- to 120-point scale), no differences were observed for ORG (71.3) and CONV (69.2) steers for overall consumer liking of the beef; however, the GRS (56.3) steers had the lowest overall liking among beef consumers. The ORG (73.3) steers had greater flavor liking than the GRS (56.8) and CONV (69.2) steers. Conversely, the GRS (6.3) steers had the highest scores for off-flavor (0- to 20-point scale) compared with the ORG (3.9) and CONV (4.1) steers. The results of the current study suggest that a potential market may exist for organic grass-fed dairy steers in the United States, but quality and consistency of the beef needs to be improved.     

Comparing microwave- and water bath-thawed starch-based sauces: Infrared thermography,rheology and microstructure

The purpose of this study was to compare the effects of microwave thawing and water bath thawing on white sauces prepared with two different native starches (potato and corn) and a modified waxy maize starch. The linear viscoelasticity, microstructure and thermographic characteristics of the thawed sauces were analysed and compared with those of freshly prepared sauces. Due to starch retrogradation, the quality characteristics of the native starch-based sauces were strongly affected by freezing and thawing, but these effects were smaller for microwave heating than for heating in a water bath. The water accumulated during freezing tended to diffuse more uniformly in the microwave-thawed sauces, providing a more homogeneous structure than that of the water bath-thawed sauces. It is hypothesized that the shorter heating time in microwave reduces the extent of starch retrogradation during thawing and that local high temperature zones in the microwave may be more effective in the melting of retrograded starch.     

The pasting,chemical and sensory properties of biofortified cassava root starch-based custard powder

The effect of biofortified cassava root starch (YfCRS) (90–98 %) and whole egg powder (WEP) (2–10 %) on the pasting, chemical and sensory properties of cassava starch-based custard powder (CbCP) were studied using response surface methodology. The result revealed that there are variations in the pasting properties of the CbCP notwithstanding the levels of WEP inclusion, and all the custard powder could form paste below the boiling point of water at the peak time of <5 min. Additionally, the CbCP with high quantity of WEP had the highest protein (6.39 %), iron (29.39 mg/kg) and zinc (4.25 mg/kg) contents, but with low amylose (18.68 %) and trans-β-carotene (0.0756 μg/g) contents. The YfCRS increased the amylose and trans-β-carotene contents of the custard powder. The models for the responses were highly adequate (R² > 80 %), except for peak viscosity, pasting temperature, hydrogen cyanide and overall acceptability. Although all the sensory attributes of the formulated CbCP gruel fall within the likeness range, 93.13 % YfCRS and 7.56 % WEP is the optimum combinations for good quality CbCP. Therefore, to replace maize starch with cassava starch in the production of a quality CbCP, 93.13 % YfCRS and 7.56 % WEP could be used.     

Rheological properties,stability and sensory evaluation of low-cholesterol mayonnaises prepared using egg yolk granules as emulsifying agent

No important practical applications have been developed for egg yolk granules until now. However, as they have low cholesterol content and maintain good emulsifying properties, granules could be employed as a potential ingredient in the food industry. In this work, granules obtained in the laboratory by a simple procedure were used as emulsifying agent in mayonnaise preparation. The aim was to develop a low-cholesterol mayonnaise with properties similar to those of typical mayonnaise. For this purpose, three low-cholesterol formulations prepared in the laboratory were compared with a mayonnaise prepared using yolk and also with a commercial mayonnaise. The rheological characteristics of mayonnaises were evaluated, as well as their microstructure and sensorial properties. In addition, colour and particle size measurements at different times of storage were carried out to assess stability. According to results, the use of granules allows the preparation of a low-cholesterol mayonnaise which shows similar characteristics to those of a typical mayonnaise.     

Microbiological safety of mayonnaise, salad dressings, and sauces produced in the United States: a review

The literature on the death and survival of foodborne pathogens in commercial mayonnaise, dressing, and sauces was reviewed and statistically analyzed with emphasis on Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes. The absence of reports of foodborne illness associated directly with the consumption of commercially prepared acidic dressings and sauces is evidence of their safety. Salmonella, E. coli O157:H7, E. coli, L. monocytogenes, Staphylococcus aureus, and Yersinia enterocolitica die when inoculated into mayonnaise and dressings. Historically, mayonnaise and dressings have been exempt from the acidified food regulations and have justly deserved this status due primarily to the toxic effect of acetic and to a lesser extent lactic and citric acids. These organic acids are inimical to pathogenic bacteria and are effective natural preservatives with acetic being the most effective in killing pathogenic bacteria at the pH values encountered in these products. Statistical analysis on data reported in the literature shows that the most important and significant factor in destroying pathogenic bacteria is pH as adjusted with acetic acid followed by the concentration of acetic acid in the water phase. The reported highest manufacturing target pH for dressings and sauces is 4.4, which is below the 4.75 pKa of acetic acid and below the reported inhibitory pH of 4.5 for foodborne pathogens in the presence of acetic acid. The overall conclusion is that these products are very safe. They should remain exempt from the acidified food regulations providing adequate research has been done to validate their safety, and the predominant acid is acetic and reasonable manufacturing precautions are taken.     

Extensively reared Iberian pigs versus intensively reared white pigs for the manufacture of frankfurters

Physico-chemical characteristics and different quality traits of the raw material (meat and adipose tissue) and the frankfurters elaborated from extensively reared Iberian pigs (IF) and intensively reared white pigs (WF) were evaluated. Hybrid frankfurters (HF) made with meat from white pigs and adipose tissue from Iberian pigs were also studied. The differences found between muscles and adipose tissues from Iberian and white pigs largely influenced the characteristics displayed by the frankfurters. Particularly remarkable are the higher amounts of substances with proven antioxidant activity such as tocopherols and phenolic compounds in tissues from Iberian pigs than in those from white pigs. No significant differences were found amongst frankfurters for their proximate composition though IF presented a higher iron content than WF and HF. IF exhibited a redder and darker colour than WF and HF. The latter were paler and showed higher hue values than IF. Concerning their fatty acid composition, IF had higher proportions of oleic acid and MUFA and smaller proportions of SFA and PUFA than WF. From a nutritional point of view, IF had a lower n-6/n-3 value than WF. The addition of adipose tissue from Iberian pigs to the HF modified its fatty acid composition compared to that of WF, significantly increasing the percentages of MUFA and reducing the proportions of PUFA, SFA and the n-6/n-3 value. Though no significant differences were found amongst frankfurters for their texture profile, a clear trend was detected, with the HF showing intermediate texture characteristics between IF and WF.     

Effect of thermosonication on peroxidase,pectin methylesterase activities and on bioactive compounds in custard apple juice

Custard apple juice faces long term storage challenges such as pink discoloration and bitterness due to peroxidase activity. Therefore, inactivation of peroxidase becomes a necessity for longer shelf life of custard apple and its application in food preparations. Heat processing has certain pitfalls such as loss in nutritional contents of custard apple juice, thereby adversely affecting the sensory quality. In the present study, thermosonication of custard apple juice at a constant temperature of 30?±?1?°C (20 kHz, 67.84 W/cm²) from 0 to 40 min has been studied with respect to peroxidase and pectin methylesterase inactivation. Effect of thermosonication has also been studied on bioactive components such as total phenolics and flavonoids along with enzyme inactivation. Complete inactivation of peroxidase and pectin methylesterase with 0% residual activity was achieved within 40 min and 50 s, respectively. Total phenolics were found to increase from 70.9?±?1.6 to 81.7?±?2.5 mg GAE/g. Sonication was found to have no significant effect (P?>?0.05) on pH, °Brix, titratable acidity. Ascorbic acid content remained relatively unaffected during sonication. Hence, thermosonication may be employed as food processing technique where retention of bioactive components have been achieved along with safety and quality attributes.     

Fatty acids composition and rheology properties of wheat and wheat and white or brown rice flour mixture

Manufacturing of bread from rice flour only presents technological difficulty because the rice is gluten-free and gluten is the most important structure forming protein. By using wheat and rice flour mixture, this problem can be avoided, and end product is enriched by rice-oil constituents. In this paper fatty acids composition, with an emphasis on total saturated, and total unsaturated fatty acids, rheological and baking properties of wheat–rice flour mixture (70:30 w/w) were investigated. The results show that wheat–rice flour mixture has better fatty acids composition with higher content of stearic, arachidic, lignoceric, oleic, and phthalic acids compared to wheat flour. Also, wheat flour did not include myristic, arachidic, lignoceric and linolenic acids, so rice flour addition made fatty acids profile richer as number of constituents is higher, nine instead six. The content of total unsaturated fatty acids content was higher in wheat–brown rice flour mixture than in wheat flour and in wheat–white rice flour mixture. When rice flour was added to wheat flour the rheological properties were changed: flour mixture had less water absorption, less degree of softening, longer development time, higher gelatinization temperature, but better stability and finally, better quality number and group than wheat flour. So, the wheat and rice flour mixture can be considered as a good quality flour and can be used for making good quality wheat-rice bread and cake.