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  • Study of the proximate and mineral composition of different Nigerian yam chips, flakes and flours
    Publication . Omohimi, C. I.; Piccirillo, C.; Roriz, M.; Ferraro, V.; Vasconcelos, M. W.; Sanni, L. O.; Tomlins, K.; Pintado, M. M.; Abayomi, L. A.
    Yam (Dioscorea spp) is an essential tuber crop for hundreds of millions of people in many African, Asian and South American countries. Considering in particular Southwest Nigeria, chips, flakes and flours are amongst the most common shelf-stable traditionally-processed yam products. This paper reports a systematic study on the proximate (moisture, protein, carbohydrate, fibre, fat, ash and gross energy) and mineral composition of these three food commodities sold in Nigerian markets. Results showed no significant differences in the moisture, crude protein and fibre content of all samples (10.0–12.3, 2.7–4.3 and 1.3–2.0 wt%, respectively). Gross energy was also comparable for all yam derived food items (between 3300 and 3507 kcal/kg), contradicting the common belief that yam flakes have lower nutritional value than chips and flours. Considering the mineral composition, Ca, Mg, P and K were the predominant macronutrients. Micronutrients such as Zn, Co, Mn and Cu were also detected. Significant differences existed between products, and their various sources (markets). Principal component analysis showed a direct correlation between ash content of the samples and the assessed macronutrients, irrespective of the market, or the seller of the commodities. This study confirmed that yam derived food stuffs have an adequate nutritional composition, irrespective of their form and/or origin.
  • Cassava (manihot esculenta crantz) and yam (dioscorea spp.) crops and their derived foodstuffs: safety, security and nutritional value
    Publication . Ferraro, Vincenza; Piccirillo, Clara; Tomlins, Keith; Pintado, M. E.
    Cassava (Manihot esculenta Crantz) and yam (Dioscorea spp.) are tropical crops consumed by ca. 2 billion people and represent the main source of carbohydrate and energy for the approximately 700million people living in the tropical and sub-tropical areas. They are a guarantee of food security for developing countries. The production of these crops and the transformation into food-derived commodities is increasing, it represents a profitable business and farmers generate substantial income from their market. However, there are some important concerns related to the food safety and food security. The high post-harvest losses, mainly for yam, the contamination by endogenous toxic compounds, mainly for cassava, and the contamination by external agents (such as micotoxins, pesticides, and heavy metal) represent a depletion of economic value and income. The loss in the raw crops or the impossibility to market the derived foodstuffs, due to incompliance with food regulations, can seriously limit all yam tubers and the cassava roots processors, from farmers to household, from small-medium to large enterprises. One of the greatest challenges to overcome those concerns is the transformation of traditional or indigenous processing methods into modern industrial operations, from the crop storage to the adequate package of each derived foodstuff.
  • Consumer acceptance and sensory profiling of reengineered kitoza products
    Publication . Pintado, Ana I. E.; Monteiro, Maria João; Talon, Régine; Leroy, Sabine; Scislowski, Valérie; Fliedel, Geneviève; Rakoto, Danielle; Maraval, Isabelle; Costa, Ana I. A.; Silva, Ana P.; Pallet, Dominique; Tomlins, Keith; Pintado, M. E.
    Kitoza refers to a traditional way of preparing beef and pork in Madagascar. However, in order to improve some drawbacks previous identified, the product was submitted to a reengineering process. The acceptance and sensory profiling of improved Kitoza products among Portuguese consumers was investigated. A local smoked loin sausage was selected as basis for comparison. Firstly, a Focus Group study was performed to identify sensory descriptors for Kitoza products and explore product perception. Subsequently, a Flash Profile and a consumer sensory acceptance study were conducted. Flash Profile's results showed that beef- and pork-based Kitoza products investigated differed considerably in all sensory dimensions. The Portuguese sausage was characterized as having a more intense and lasting after taste, as well as displaying a higher degree of (meat) doneness. The acceptance study yielded higher overall liking ratings for pork- than for beef-based Kitoza, although the Portuguese sausage remained the most appreciated product.
  • Chemical-sensory properties and consumer preference of hibiscus beverages produced by improved industrial processes
    Publication . Monteiro, Maria João P.; Costa, Ana Isabel A.; Fliedel, Geneviève; Cissé, Mady; Bechoff, Aurélie; Pallet, Dominique; Tomlins, Keith; Pintado, Maria Manuela E.
    The need to increase sustainability and add value to traditional foods claiming health benefits led to the introduction of key improvements in the production of hibiscus beverages in Senegal. The physicochemical and sensory properties of three resulting products (an under-vacuum concentrate, a dilute-to-taste syrup and a ready-to-drink infusion) were assessed, vis-à-vis those of conventionally manufactured beverages, and their impact on local consumer preference determined (n=146). New beverages had more intense, redder colour and higher monomeric anthocyanin content, total phenolic content and antioxidant capacity. Moreover, their colour evaluations by trained panellists were mainly linked to colour density and anthocyanin/polyphenol content, while flavour assessments were associated to titratable acidity and sugar-to-acid ratio. Consumer evaluations, in turn, were driven by the beverages' red colour intensity, aroma strength and balance between sweetness and acidity. This explained why they overwhelmingly preferred the under-vacuum concentrate, regardless of their age, gender or frequency of hibiscus beverage consumption.
  • Relationships between anthocyanins and other compounds and sensory acceptability of Hibiscus drinks
    Publication . Bechoff, Aurélie; Cissé, Mady; Fliedel, Geneviève; Declemy, Anne-Laure; Ayessou, Nicolas; Akissoe, Noel; Touré, Cheikh; Bennett, Ben; Pintado, Manuela; Pallet, Dominique; Tomlins, Keith I.
    Chemical composition of Hibiscus drinks (Koor and Vimto varieties, commercial and traditional, infusions and syrups) (n = 8) was related to sensory evaluation and acceptance. Significant correlations between chemical composition and sensory perception of drinks were found (i.e. anthocyanin content and Hibiscus taste) (p < 0.05). Consumers (n = 160) evaluated drink acceptability on a 9-point verbal hedonic scale. Three classes of behaviour were identified: (a) those who preferred syrup (43% of consumers); (b) those who preferred infusion (36%); and (c) those who preferred all of the samples (21%). Acceptability of ‘syrup likers’ was positively correlated to sweet taste, reducing sugar content and inversely correlated to acidic taste and titratable acidity (p < 0.10). Acceptability of ‘infusion likers’ was positively correlated to the taste of Hibiscus drink and anthocyanin content. The study showed that the distinctions between the acceptability groups are very clear with respect to the chemical composition and rating of sensory attributes
  • Cross-cultural development of hibiscus tea sensory lexicons for trained and untrained panelists
    Publication . Monteiro, Maria João P.; Costa, Ana Isabel A.; Franco, Maria Isabel; Bechoff, Aurelie; Cisse, Mady; Geneviève, Fliedel; Tomlins, Keith; Pintado, Maria Manuela E.
    Given the growing interest in high quality hibiscus teas and the scarcity of information about their sensory profile, lexicons were developed in French, Portuguese, and English. Twenty‐two samples, including freshly prepared and ready‐to‐drink (RTD) infusions, syrups, concentrates, and an instant tea were evaluated by trained panelists, resulting in 21 defined and referenced descriptors, subsequently assembled in a sensory wheel. The vocabulary used by untrained panelists was investigated in Senegal, Portugal, France, and United Kingdom through professional meetings (n = 30), consumer focus groups (n = 75) and check‐all‐that‐apply (CATA) studies (n = 490), resulting in graphical lexicons with 27 sensory and 15 overall impression terms. Training, food culture, and product familiarity influenced results. Trained panelists used precise terms to describe the aromatic profile of hibiscus teas (e.g., “reminiscent of dried hibiscus flowers,” with “berry,” “raisin,” “hay,” and “sweet” aromatic notes), whereas untrained ones were more prolific in general expressions (e.g., “strong in hibiscus” in Senegal; “floral” and “fruity” in Europe).