Linda Malcolmson

Textural analysis of fat reduced vanilla ice cream products

Abstract Sensory and instrumental analyses were used to evaluate the texture of regular (10%), light (5%), low fat (2.5%) and fat free vanilla (0.4%) ice creams. The light, low fat and fat free ice cream were prepared using a modified pea starch as the fat replacement ingredient. Two processing trials with continuous commercial-like process conditions were undertaken. While the sensory attributes of the light sample were comparable to the regular vanilla ice cream, the trained sensory panel rated the low fat and fat free ice creams to have lower viscosity, smoothness and mouth coating properties. Instrumentally determined apparent viscosity data supported the sensory data. There was good correlation between the instrumentally determined firmness values and the sensory results for firmness. The use of modified starch as a partial fat replacer in vanilla ice cream was demonstrated.

Bioavailability of Alpha-Linolenic Acid in Subjects after Ingestion of Three Different Forms of Flaxseed

Background: Dietary flaxseed may have significant health-related benefits due to its high content of the omega-3 fatty acid, alpha-linolenic acid (ALA). However, before extensive work can be undertaken in clinical populations to determine its efficacy, basic information on ALA bioavailability from flaxseed and the physiological effects of its ingestion need to be examined. Objective: The purpose of this study, therefore, was to determine the bioavailability of ALA when the flaxseed was ingested in the form of whole seed, milled seed or as flaxseed oil. Design: The flaxseed components (30 g of seed or 6 g of ALA in the oil) were baked into muffins for delivery over a 3 month test period in healthy male and female subjects. Results: Flaxseed ingestion over a 1 month period resulted in significant (P = 0.005) increases in plasma ALA levels in the flaxseed oil and the milled flaxseed supplemented groups. The former group had significantly (P = 0.004) higher ALA levels than the milled flaxseed group. The subjects supplemented with whole flaxseed did not achieve a significant (P > 0.05) increase in plasma ALA levels. An additional two months of flaxseed ingestion did not achieve significantly higher levels of plasma ALA in any of the groups. However, no significant increase was detected in plasma eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) levels in any of the flax-fed groups. There were no changes in plasma cholesterol or triglycerides or in platelet aggregation at any time point in any of the groups. Subjects in all of the groups exhibited some symptoms of gastro-intestinal discomfort during the early stages of the study but these disappeared in the oil and milled seed groups. However, compliance was a problem in the whole flaxseed group. Conclusion: In summary, ingestion of flax oil and milled flaxseed delivered significant levels of ALA to the plasma whereas whole flaxseed did not. Whole seed and oil preparations induced adverse gastrointestinal effects within 4 weeks and these were severe enough to induce the withdrawal of some subjects from these two groups. No one withdrew from the group that ingested milled flaxseed and, therefore, may represent a good form of flaxseed to avoid serious side-effects and still provide significant increases in ALA to the body.

Dietary milled flaxseed and flaxseed oil improve N-3 fatty acid status and do not affect glycemic control in individuals with well-controlled type 2 diabetes.

Objective: To determine the effects of dietary consumption of milled flaxseed or flaxseed oil on glycemic control, n-3 fatty acid status, anthropometrics, and adipokines in individuals with type 2 diabetes. Design: Thirty-four participants were randomized into a parallel, controlled trial. Subjects: The participants were adults with type 2 diabetes (age 52.4 ± 1.5 years, body mass index 32.4 ± 1.0 kg/m2, n  =  17 men and 17 women). Interventions: Participants consumed a selection of bakery products containing no flax (control group [CTL], n  =  9), milled flaxseed (FXS, n  =  13; 32 g/d), or flaxseed oil (FXO, n  =  12; 13 g/d) daily for 12 weeks. The FXS and FXO groups received equivalent amounts of alpha-linolenic acid (ALA; 7.4 g/day). Measures of Outcome: The primary outcome measures were fasting plasma hemoglobin A1c, glucose, insulin, and phospholipid fatty acid composition. The secondary outcome measures were fasting circulating leptin and adiponectin, as well as body weight, body mass index, and waist circumference. Dietary intake assessment and calculations for homeostasis model assessment for insulin resistance and quantified insulin sensitivity check were also completed. Results: The FXS and FXO groups had increases in plasma phospholipid n-3 fatty acids (ALA, eicosapentaenoic acid [EPA], or decosapentaenoic acid [DPA], but not docosahexaenoic acid), and the FXO group had more EPA and DPA in plasma phospholipids compared to the FXS group. All groups had similar caloric intakes; however, the CTL group experienced a 4% weight gain compared to baseline (p < 0.05), while both flax groups had constant body weights during the study period. All other parameters, including glycemic control, were unchanged by dietary treatment. Conclusions: Milled FXS and FXO intake does not affect glycemic control in adults with well-controlled type 2 diabetes. Possible prevention of weight gain by flax consumption warrants further investigation.

Effect of tempering and end moisture content on the quality of micronized lentils

The use of micronization (infrared treatment) on grain legumes tempered with water has potential for reducing cooking times. Using Laird lentils, the effects of tempering conditions and moisture content following micronization were evaluated in terms of color, chemical properties and texture after 15 min cooking. The texture of cooked lentils softened as tempering moisture increased. This was related to increasing starch gelatinization and decreasing protein solubility during micronization. Changes in the pectic substances did not appear to influence texture. The reduction in hardness indicates that shorter cooking times are required for samples micronized under high moisture conditions. Lentil color changed slightly under these high moisture conditions as evidenced by the Hunterlab readings.

Micronization pretreatments for reducing the cooking time of lentils

For many grain and grain legume crops, a pretreatment step is often employed prior to processing to improve the quality of the final product. The pretreatment may be tempering, where a uniform specified moisture content in the grain is desired, or soaking, where moisture content is high and unevenly distributed. This study evaluated the effect of moisture contents and reagents as potential pretreatments for micronization (infrared heat treatment) of lentils, the objective being to reduce lentil cooking times. The texture of over-, under- and optimally cooked lentils was defined by sensory methods and by peak force values at 40% compression. As cooking time increased, sensory scores for hardness, chewiness and particle size decreased, as did peak force values. The peak force for optimally cooked lentils receiving no pretreatment was the control used to assess the effectiveness of a given pretreatment. The pretreatments studied were soaking of lentils, tempering of lentils to 20 or 40% moisture with water alone, and tempering to 20 or 40% moisture with solutions of various reagents: sodium salts of carbonate, bicarbonate, phosphate, tripolyphosphate and EDTA, and mixtures of citric and ascorbic acids. For tempering pretreatments, cooking time was reduced as moisture increased, but it was only at 40% moisture that added reagents were effective in reducing lentil cooking times. It was postulated that free water must be available in the cotyledon to allow reagents in the tempering water to reduce cooking time beyond that attainable with water alone. Potential reagents for tempering solutions used as successful micronization pretreatments were 2% sodium tripolyphosphate, mixtures of 1% citric and 2% ascorbic acid, and 150 ppm disodium EDTA.

Incorporation of pulse flours of different particle size in relation to pita bread quality

BACKGROUND To increase pulse consumption, pita bread was fortified with pulse flours milled from green lentils, navy beans and pinto beans, which were ground to produce fine and coarse flours. Pita breads were prepared using composite flours containing pulse flours (25, 50, 75%) and wheat flour or 100% pulse flours and adjusting the amount of water required for mixing based on farinograph water absorption. Pita bread quality was evaluated according to diameter, pocket height, specific loaf volume, texture and crust colour. RESULTS Blends made from pulse flours with coarse particle size showed higher rates of water absorption. All composite flours and 100% pulse flours produced pitas with pockets, confirming their suitability for this product. Crust colour of pitas was affected less by navy bean flour than by lentil flour. Pita breads made with pinto bean flour were superior in texture. Overall, navy and pinto bean flours appeared more suitable for pita bread. Flours with coarse particle sizes produced pitas with better colour and texture. Sensory parameters of pitas containing 25% coarse pinto or navy bean flour were as good as or better than those from the wheat control. CONCLUSION Acceptable pita breads can be made using pulse flours, although the substitution level is limited to 25%.

Techno-functional characterization of salad dressing emulsions supplemented with pea, lentil and chickpea flours.

BACKGROUND Salad dressings supplemented with pulse flours are novel products. A three-factor face-centered central composite design (CCD) was used to determine the effect of pulse flour concentration (3.5%, 7%, 10.5% w/w), egg yolk concentration (3%, 5%, 7% w/w) and oil concentration (20%, 35%, 50% w/w) on the rheological and color characteristics of salad dressings supplemented with pulse flours. RESULTS The consistency coefficient m, plateau modulus G(N)(0), recoverable strain Q(t) and color values were all affected by the concentrations of pulse flours used. Scanning electron microscopy showed that dressings with lower oil and egg yolk contents had a less densely packed network compared with dressings with higher oil and egg yolk contents. Sensory results were most promising for salad dressings supplemented with the whole green lentil, yellow pea with low flour content, and chickpea with high oil content. CONCLUSION This study should be useful for designing novel types of salad dressings to meet market requirements as well as helping to increase pulse consumption.

Application of Gas Chromatography in the Analysis of Flavour Compounds in Field Peas

Flavour compounds influence the taste and quality of foods both of which are very important criteria in food selection and consumer acceptance. Pulse legumes such as field peas are increasingly used in foods such as soup mixes, purees, bakery and other processed products (Heng et al., 2004). In some parts of the world, particularly in Western countries, the presence of off-flavours in peas can be an obstacle to their consumption.

Effect of milling treatments and storage conditions on the dehulling characteristics of red lentils.

Milling is an important process in the post-harvest handling of red lentils. The effect of milling moisture content, milling speed and milling time on the dehulling characteristics of two varieties of red lentils, CDC Impact and CDC Redberry, was investigated. Response surface methodology with a central composite design was used to determine optimum milling conditions. Optimum milling conditions included: milling moisture content of 12.5%, milling speed of 1,100 RPM and dehulling time of 38 s. Milling with these parameters resulted in dehulling efficiencies of ≥ 85%. Various treatments (high heat drying, near ambient drying, and successive freezing and thawing cycles) were employed to simulate different storage conditions. Dehulling efficiency of both red lentil varieties was negatively affected by drying yet dehulling quality was not adversely affected by freezing and thawing. This work provides information necessary to establish post-harvest techniques that maximise the dehulling efficiency of red lentils.