Browsing by Author "Raes, Katleen"

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Chapter 8 - Current trends and opportunities of plant-based non-alcoholic probiotic beverages: A European and African perspective
(Elsevier, 2021-05) Mandha, Juliana; Shumoy, Habtu; Matemu, Athanasia; Raes, Katleen
Although dairy-based foods have been the main probiotic food sources, a range of plant-based products are currently being developed to meet the needs of vegetarians, lactose intolerant persons, individuals on low cholesterol diets or allergic to milk proteins. This chapter reviews the plant based non-alcoholic probiotic beverages in Europe and Africa. It begins with an introduction of regulations that govern the production, safety and marketing of probiotic beverages in Europe and Africa, followed by a discussion of the commercial, traditional, and experimental studies of plant-based non-alcoholic beverages, categorized as cereals, vegetable/legume, and fruit-based probiotic beverages.
Characterization of fruit juices and effect of pasteurization and storage conditions on their microbial, physicochemical, and nutritional quality
(Elsevier Ltd., 2023-02) Mandha, Juliana; Shumoy, Habtu; Matemu, Athanasia; Raes, Katleen
Characterization, pasteurization and storage are essential steps in fruit juice processing. Watermelon, pineapple, and mango juices were pasteurized at 80 ± 2 °C and held at different treatment times (1, 2.5, 5, 10, and 15 min). Juice yield, pH, proximate composition, total soluble solids, color, vitamin C, microbial quality, mineral content, enzyme activity (polyphenol oxidase (PPO), and peroxidase (POD)), total phenolic content, and antioxidant capacity were measured during pasteurization and cold storage (4 °C). Results showed that watermelon juice had the highest crude protein, pH, and moisture content, pineapple juice had the highest titratable acidity, vitamin C and mineral content (potassium, calcium, magnesium, manganese, and zinc) and mango juice had the highest juice yield, and total soluble solids. Regardless of the holding time, pasteurization reduced total plate counts and yeast and molds to below detectable limits (1 log CFU/mL). Vitamin C was undetectable in watermelon juice after 10 min of pasteurization compared to mango juice with a 27% reduction. Pasteurization preserved mango juice color, but watermelon juice became less red and more yellow with increasing treatment time. POD was more thermoresistant than PPO and needed a treatment time of at least 5 min to obtain 80% reduction. Storage of more than 9 days negatively affected the watermelon color, total phenolic content and antioxidant capacities of watermelon juice pasteurized at 15 min and vitamin C content of unpasteurized mango juice. Thus, pasteurization and storage affect fruit juice quality depending on the type of fruit and their composition.
Effect of lactic acid fermentation of watermelon juice on its sensory acceptability and volatile compounds
(Elsevier Ltd., 2021-10-01) Mandha, Juliana; Shumoy, Habtu; Devaere, Jolien; Schouteten, Joachim; Gellynck, Xavier; de Winne, Ann; Matemu, Athanasia; Raes, Katleen
Fermentation increases food shelf-life but is characterized by changes that affect product's perception. Watermelon juice was fermented with Lactobacillus plantarum (WJ-LP), L. rhamnosus (WJ-LR), L. casei (WJ-LC), L. brevis (WJ-LB) and Pediococcus pentosaceus (WJ-PP). Their sensory characteristics and volatile compounds were investigated by consumers and Headspace Solid Phase Microextraction integrated with Gas Chromatography-Mass Spectrometry, respectively. WJ-PP and WJ-LB were most liked and perceived with ‘watermelon-flavor’, ‘natural taste’, ‘sweet’ and ‘watermelon-color’ while WJ-LC, WJ-LP and WJ-LR were least liked and perceived as ‘sour’, ‘bitter’, ’off-flavor’, ‘aftertaste’ and ‘intense-flavor’. Fifty-four volatiles were identified. After fermentation, alcohols, ketones, monoterpenes, acids, and furans increased while aldehydes and alkanes decreased. Lactic acid fermentation introduced 4-decanone and 2,3-butanedione in WJ-LB, WJ-LC, WJ-LP and WJ-LR, however, heptanal, 2-heptenal, 2,6-nonadienal, 2-decenal, and 2,4-decadienal in WJ-LC, heptanal, 2-hexenal, 2-heptenal, 2,6-nonadienal, 2-decenal and octanal in WJ-LR and 2,6-dimethyl-2,6-octadiene in WJ-LP disappeared. Juice sensory profiles were associated with their volatile compounds.
Effect of Lactic Acid Fermentation on Volatile Compounds and Sensory Characteristics of Mango (Mangifera indica) Juices
(MDPI, 2022-01-28) Mandha, Juliana; Shumoy, Habtu; Devaere, Jolien; Schouteten, Joachim; Gellynck, Xavier; De Winne, Ann; Matemu, Athanasia; Raes, Katleen
Fermentation is a sustainable bio-preservation technique that can improve the organoleptic quality of fruit juices. Mango juices were fermented by monoculture strains of Lactiplantibacillus plantarum subsp. plantarum (MLP), Lacticaseibacillus rhamnosus (MLR), Lacticaseibacillus casei (MLC), Levilactobacillus brevis (MLB), and Pediococcus pentosaceus (MPP). Volatile compounds were sorbed using headspace solid phase microextraction, separated, and identified with gas chromatography mass spectrometry. Forty-four (44) volatile compounds were identified. The control, MPP, and MLB had higher amounts of ethyl acetate, ethyl butyrate, 2-hexenal, 2,6-nonadienal, 2,2-dimethylpropanal, β-selinene, γ-gurjunene, α-copaene, and δ-cadinene, while MLC, MLP, and MLR had higher amounts of 2,3-butanedione and a cyclic hydrocarbon derivate. Consumers (n = 80) assessed their overall liking and characterized sensory attributes (appearance, color, aroma, flavor, consistency, acidity, and sweetness) using check-all-that-apply, and penalty analysis (just-about-right). Overall liking was associated with ‘mango color’, ‘pulp’, ‘mango aroma’, ‘sweet’, ‘natural taste’, and ‘mango flavor’ that described the control, MLB, MLC and MPP. Juices MLR and MLP were described as ‘bitter’, ‘sour’, ‘aftertaste’, and ‘off-flavor’. Multivariate analysis revealed relationships between the volatile com pounds, mango juices fermented by different lactic acid bacteria, and sensory characteristics. Thus, the type of lactic acid bacteria strains determined the volatile and sensory profile of mango juices.
Evaluation of the composition and quality of watermelon and mango juices fermented by Levilactobacillus brevis, Lacticaseibacillus casei and Pediococcus pentosaceus and subsequent simulated digestion and storage
(John Wiley & Sons, Inc., 2022-05-29) Mandha, Juliana; Shumoy, Habtu; Matemu, Athanasia; Raes, Katleen
This study evaluated the composition of watermelon and mango juices fermented by Levilactobacillus (L.) brevis, Lacticaseibacillus (La.) casei and Pediococcus (P.) pentosaceus and subsequently simulated in vitro digestion and storage (4°C for 35 days). After fermentation (24 h), the microorganisms grew (~9 log CFU mL−1) and fermented watermelon (FWJ) and mango juice (FMJ) became more red and yellow, respectively. DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) free radical scavenging capacities significantly increased in L. brevis and La. casei FMJ. After in vitro digestion, all the strains except La. casei in FMJ significantly decreased (P < 0.05), and P. pentosaceus survival was 2.4 and 4.5 times higher in FWJ and FMJ, respectively, than as pure culture. After storage, cell counts remained above 7 log CFU mL−1, and no changes in quality attributes, total phenolic content and antioxidant capacity were recorded in P. pentosaceus FMJ. Thus, watermelon and mango are suitable matrices for lactic acid bacteria.
Valorization of Mango By-Products to Enhance the Nutritional Content of Maize Complementary Porridges
(MDPI, 2022-07-15) Mandha, Juliana; Shumoy, Habtu; Matemu, Athanasia; Raes, Katleen
Mango by-products are disregarded as waste contributing to greenhouse gas emissions. This study used mango seed and kernel to enhance the nutritional content of maize complementary porridges. Composite maize-based porridges (MBP) were formulated by fortifying maize flour with fine ground mango seed and kernel at different levels (31%, 56%, 81%). The by-products and formu lated porridges were characterized for their nutritional composition, mineral content, total phenolic content, and antioxidant capacity. Furthermore, the bioaccessibility of essential minerals during in vitro gastrointestinal digestion of the formulated porridges was determined using inductively coupled plasma optical emission spectrometry. Mango seed had a high fat (12.0 g/100 g dw) and protein content (4.94 g/100 g dw), which subsequently doubled the fat content of the porridges. Mango by-products increased the total phenolic content of maize porridge by more than 40 times and the antioxidant capacity by 500 times. However, fortification with mango by-products significantly decreased the bioaccessibility of minerals, especially manganese, copper, and iron, as the highest percentages of insoluble minerals were recorded in MBP 81 at 78.4%, 71.0%, and 62.1%, respectively. Thus, the results suggest that mango seed and kernel could increase the nutritional value of maize porridge, but fortification should be done at lower levels of about 31–56%.Mango by-products are disregarded as waste contributing to greenhouse gas emissions. This study used mango seed and kernel to enhance the nutritional content of maize complementary porridges. Composite maize-based porridges (MBP) were formulated by fortifying maize flour with fine ground mango seed and kernel at different levels (31%, 56%, 81%). The by-products and formu lated porridges were characterized for their nutritional composition, mineral content, total phenolic content, and antioxidant capacity. Furthermore, the bioaccessibility of essential minerals during in vitro gastrointestinal digestion of the formulated porridges was determined using inductively coupled plasma optical emission spectrometry. Mango seed had a high fat (12.0 g/100 g dw) and protein content (4.94 g/100 g dw), which subsequently doubled the fat content of the porridges. Mango by-products increased the total phenolic content of maize porridge by more than 40 times and the antioxidant capacity by 500 times. However, fortification with mango by-products significantly decreased the bioaccessibility of minerals, especially manganese, copper, and iron, as the highest percentages of insoluble minerals were recorded in MBP 81 at 78.4%, 71.0%, and 62.1%, respectively. Thus, the results suggest that mango seed and kernel could increase the nutritional value of maize porridge, but fortification should be done at lower levels of about 31–56%.