RESUMEN
BACKGROUND: Vacuum package storage is commonly applied to reduce postharvest deterioration in minimally processed cassava roots. However, the influence of vacuum packaging conditions on root end-use quality is poorly understood. Hence, the effects of vacuum packaged storage at ambient, refrigerated and freezing temperatures on microflora, cassava tissue structure and starch extraction by wet milling were studied. RESULTS: Vacuum packaged storage temperature strongly affected cassava root quality. Minimal adverse effects were obtained with frozen storage. With refrigerated storage, there was negligible microbial growth but some disruption of the parenchyma cell wall structure suggestive of chilling injury. With ambient temperature storage, there was considerable Lactobacilli dominated fermentation. This caused substantial cell degradation, probably due to the production of extracellular cellulolytic and other cell wall degrading enzymes. A benefit of this cell wall breakdown was that it substantially improved starch extraction with wet milling from the stored cassava pieces; by 18% with pieces that had been ambient vacuum packaged and wet milled using a 2000 µm opening screen. However, ambient temperature storage resulted in some starch granule pitting due to the action of extracellular amylases from the fermenting microorganisms. CONCLUSION: The best vacuum packaging storage conditions for minimally processed cassava depends on application and cost. For short-term storage, refrigeration would be best for vegetable-type products. For several months storage, freezing is best. For wet milling applications, this could be combined with subsequent short-term ambient temperature storage as it improves starch extraction efficiency and could reduce distribution energy costs. © 2021 Society of Chemical Industry.
Asunto(s)
Embalaje de Alimentos/métodos , Manihot/química , Tubérculos de la Planta/química , Almidón/aislamiento & purificación , Manipulación de Alimentos , Embalaje de Alimentos/economía , Embalaje de Alimentos/instrumentación , Almacenamiento de Alimentos , Almidón/análisis , Temperatura , VacioRESUMEN
BACKGROUND: The challenges of malnutrition and urbanization in Africa demand the development of acceptable, affordable, nutritious complementary-type foods. Biscuits (i.e. cookies; a popular snack) from whole grain staples are an option. The present study aimed to relate check-all-that-applies (CATA) sensory profiles of sorghum-cowpea composite biscuits compared to economic commercial refined wheat biscuits with hedonic ratings by low income consumers. In addition, the nutritional composition and protein quality, L* a* b* colour and texture of the biscuits were determined. RESULTS: The CATA method is suitable for rapidly determining which attributes consumers perceive in food products and relating these to acceptability. Consumers preferred the lighter, more yellow wheat biscuits with ginger, vanilla, sweet and cinnamon flavours compared to the stronger flavours (sorghum, beany and nutty) and harder but brittle, grittier, dry and rough textured sorghum or sorghum-cowpea biscuits. However, a substantial proportion of consumers also liked the latter biscuits. The composite biscuits had higher dietary fibre content and a similar protein quality to the standards. CONCLUSIONS: Whole grain sorghum-cowpea biscuits could serve as acceptable value-added nutritious complementary snacks for consumers in sub-Saharan Africa. The biscuits are simple to produce for the creation of viable small enterprises. © 2017 Society of Chemical Industry.
Asunto(s)
Pan/análisis , Sorghum/química , Vigna/química , África , Preferencias Alimentarias , Humanos , Valor Nutritivo , Pobreza , Sorghum/metabolismo , Gusto , Vigna/metabolismoRESUMEN
BACKGROUND: In Africa, food-processing industries are emerging fast, especially for cereals. New low-cost extrusion cookers give small enterprises an opportunity to enter the market for processed cereal products, in particular instant, fortified and flavoured mixes. Before engaging in the marketing of these products, consumers' interest needs to be assessed. This study used a combination of affective tests and experimental auctions with 200 consumers in Touba, Senegal, to evaluate four new products with conventional pearl millet flour as the control: instant pearl millet flour, instant pearl millet flour with added dry mango and carrot powder (naturally fortified), and the previous products with added conventional chemical micronutrient fortificants. RESULTS: During affective tests, consumers made little distinction between the five products in appearance, aroma, taste and overall appreciation. The experimental auctions showed that, without providing additional information on the products, there was no difference in 'willingness to pay' (WTP) between them. However, after that information is provided, consumers were willing to pay a modest premium for instant flour, and a large premium for added mango and carrot extract and for added micronutrients, but were not willing to pay a premium if those micronutrients came from natural sources. Income increased overall WTP, while education increased WTP for instant flour. CONCLUSION: There is a potential market in low-income African countries for instant and fortified cereal food products, but likely in the higher income and education groups. The increased cost needs to be compared to the premiums consumers are willing to pay. In the next step, the new and promising products could be tested in pilot markets, with target consumers. © 2017 Society of Chemical Industry.
Asunto(s)
Alimentos Fortificados , Pennisetum/química , Adulto , Comportamiento del Consumidor , Femenino , Harina/análisis , Alimentos Fortificados/análisis , Humanos , Masculino , Persona de Mediana Edad , Distribución Aleatoria , Senegal , Gusto , Adulto JovenRESUMEN
BACKGROUND: Cowpeas stored under high temperature and humidity develop the hard-to-cook defect (HTC). This defect greatly increases cooking times and energy costs. To better understand the mechanisms involved in the HTC defect development, the effects of gamma-irradiation on cotyledon cellular structure and pectin solubility in two cowpea cultivars with different susceptibility to HTC defect were investigated. RESULTS: Gamma-irradiation decreased cotyledon cell wall thickness, increased cell size, and intercellular spaces in both cowpea cultivars and reduced cooking time of the less HTC susceptible cultivar. However, it did not reverse the HTC defect in the susceptible cultivar. Gamma-irradiation also increased the levels of cold water- and hot water-soluble pectin. The irradiation effects were thus mainly due to hydrolysis of pectin fractions in the cell walls. However, chelator-soluble pectin (CSP) solubility was not affected. CONCLUSION: As the cell wall changes brought about by gamma-irradiation were associated with pectin solubilisation, this supports the phytate-phytase-pectin theory as a major cause of the HTC defect. However, the non-reversal of the defect in HTC susceptible cowpeas and the absence of an effect on CSP indicate that other mechanisms are involved in HTC defect development in cowpeas, possibly the formation of alkali-soluble, ester bonded pectins. © 2017 Society of Chemical Industry.
Asunto(s)
Cotiledón/química , Manipulación de Alimentos/métodos , Pectinas/química , Extractos Vegetales/química , Vigna/embriología , Vigna/efectos de la radiación , Fraccionamiento Químico , Culinaria , Cotiledón/efectos de la radiación , Manipulación de Alimentos/instrumentación , Rayos gamma , Calor , Pectinas/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Solubilidad , Vigna/químicaRESUMEN
BACKGROUND: Marama bean protein, as extracted previously at pH 8, forms a viscous, adhesive and extensible dough. To obtain a protein isolate with optimum functional properties, protein extraction under slightly acidic conditions (pH 6) was investigated. RESULTS: Two-dimensional electrophoresis showed that pH 6 extracted marama protein lacked some basic 11S legumin polypeptides, present in pH 8 extracted protein. However, it additionally contained acidic high molecular weight polypeptides (â¼180 kDa), which were disulfide crosslinked into larger proteins. pH 6 extracted marama proteins had similar emulsification properties to soy protein isolate and several times higher foaming capacity than pH 8 extracted protein, egg white and soy protein isolate. pH 6 extracted protein dough was more elastic than pH 8 extracted protein, approaching the elasticity of wheat gluten. CONCLUSION: Marama protein extracted at pH 6 has excellent food-type functional properties, probably because it lacks some 11S polypeptides but has additional high molecular weight proteins. © 2017 Society of Chemical Industry.