Prebiotic flours in dairy food processing: Technological and sensory implications

Development and Characterization of Yellow Passion Fruit Peel Flour (Passiflora edulis f. flavicarpa)

In this study, the peels of the yellow passion fruit (Passiflora edulis f. flavicarpa) were used to develop a flour that was evaluated in terms of its physicochemical, microscopic, colorimetric, and granulometric characteristics, its total phenolic compound and carotenoid contents, and its antioxidant capacity. Fourier Transform Infrared (FTIR) spectroscopy measurements were employed to investigate the constituent functional groups, compounds' chemical profiles were assessed by Paper Spray Mass Spectrometry (PS-MS), and the compound's chemical profiles were evaluated by Ultra-Performance Liquid Chromatography (UPLC). This flour presented a light color, heterogeneous granulometry, high carbohydrate, carotenoid, and total phenolic compound contents with high antioxidant capacity. Scanning Electron Microscopy (SEM) showed a particulate flour, which is supposed to contribute to its compactness. FTIR demonstrated the presence of functional groups corresponding to cellulose, hemicellulose, and lignin, constituents of insoluble dietary fiber. The PS-MS analysis suggested the presence of 22 substances, covering diverse component classes such as organic, fatty, and phenolic acids, flavonoids, sugars, quinones, phenylpropanoid glycerides terpenes, and amino acids. This research demonstrated the potential of using Passion Fruit Peel Flour (PFPF) as an ingredient for food products. The advantages of using PFPF comprise the reduction of agro-industrial waste, contribution to the development of a sustainable food system, and increment of food products' functional profile. Moreover, its high content of several bioactive compounds can benefit consumers' health.

Milk fermentation with prebiotic flour of Vasconcellea quercifolia A.St.-Hil

Non-conventional food plants have bioactive compounds and a high nutritional value. Among these, Vasconcellea quercifolia has nutritional benefits, but it is also easy to cultivate and has a low production cost. In this study, the flour from the unripe fruit of V. quercifolia was evaluated in terms of its potential as a prebiotic for the probiotic bacteria Lactobacillus acidophilus and Bifidobacterium lactis. To do so, fermented milk samples were prepared with 2%, 3%, and 6% of flour and 8.25 log CFU/mL of each microorganism. Samples were analyzed in terms of the number of viable cells of L. acidophilus and B. lactis, as well as pH level, total solids, titratable acidity, and texture in the course of 21 days of storage at 4ºC. The obtained microbial viability revealed the in vitro symbiotic effect of flour from V. quercifolia on the probiotic strains of L. acidophilus and B. lactis, which reached 10.20 and 11.19 log CFU/mL, respectively, after 21 days of storage, showing a significant difference in cell growth of 1.7 and 2.5 log CFU/mL compared with the control. The pH level decreased from 4.8 to 4.5 after storage time, so it did not alter the conditions for the growth of bacteria. The physical and chemical parameters analyzed did not reveal significant differences (p > 0.05), which indicates product stability. Therefore, flour from the unripe fruit of V. quercifolia has a prebiotic property and can be used as a nutritional supplement for L. acidophilus and B. lactis.

Nutritional potential of Vasconcellea quercifolia A. St.-Hil. green fruit flour

Abstract Non-conventional food plants have a variety of bioactive compounds with nutritional value. Vasconcellea quercifolia A. St.-Hil., belonging to the Caricaceae family, is a dietary alternative with excellent nutritional composition. This study aimed at characterizing the nutritional composition of mountain papaya (V. quercifolia) green fruit flour, in order to incorporate it in a functional food. For that purpose, the flour was characterized regarding its macro and micronutrients, anti-nutritional factors, pH, water activity, and color. This flour showed contents of carbohydrate of 22.31%; protein of 9.65%; dietary fiber of 32.80%; lipids of 14.95%, 63.56% of which are unsaturated fatty acids, especially oleic acid; and ash of 9.10%, with higher concentrations for potassium, calcium and magnesium. Therefore, V. quercifolia flour had good nutritional characteristics and might be used as supplementary food.

In vitro angiotensin converting enzyme (ACE)-inhibitory and antioxidant activity of probiotic yogurt incorporated with orange fibre during storage

In the present work, the effects of orange fibre (OF) supplementation at four different concentrations (0.5%, 1%, 1.5% and 2%) on some quality properties of probiotic set yogurt produced with ABT-2 culture (containing Streptococcus thermophilus ST-20Y, Lactobacillus acidophilus LA-5 and Bifidobacterium lactis BB-12) were evaluated, during 21 days of storage. The in vitro angiotensin converting enzyme (ACE)-inhibitory activity and antoxidant capacity as well as some physicochemical and microbiological analyses of probiotic yogurts were analysed and compared with plain yogurt. At the beginning of storage, yogurt samples had high survivability for probiotic bacteria leading to viable counts (> 10⁷ CFU/g) higher than the minimum therapeutic threshold (10⁶ CFU/g). A significant influence (p < 0.05) of OF supplementation on S. thermophilus ST-20Y and B. lactis BB-12 counts was observed. While OF addition enhanced the viability of B. lactis BB-12, it caused a decrease in S. thermophilus ST-20Y counts. OF addition up to 1.5% concentration affected positively the syneresis, apparent viscosity and consistency index values of yogurt samples. ACE-inhibitory activity showed an increasing trend throughout the storage. Control yogurt had the lowest ACE-inhibitory activity at 1 day of storage, and the highest activity was obtained in yogurt containing 1% OF at the end of the storage. Also, yogurts with OF had higher antioxidant activity than the control sample at all days of storage (p < 0.05). Antioxidant activity increased until 14 days of storage in all yogurt batches, while it was decreased 21th days of storage. Briefly, this study reflected the performance of using OF as an alternative hydrocolloid to improve the quality properties and bioactivity of bio-yogurt.

Preparation and characterization of resistant starch type III from enzymatically hydrolyzed maize flour

Polysaccharides including resistant starch are categorized as dietary fiber and are used as an important prebiotic. Similar to soluble fibers, resistant starch also has a number of physiological effects that have been shown to be beneficial for health. Starch hydrolyzing enzymes, most importantly amylases, play essential roles in the production of resistant starch. This study aimed to develop α-amylase-treated maize flour with slow digestibility and unique physicochemical characteristics compared to native maize flour. In the current study, resistant starch type III from maize flour was prepared using α-amylase obtained from indigenously isolated Bacillus licheniformis. The α-amylase gene from B. licheniformis was amplified and cloned into the pET-24(a) vector, expressed in E. coli BL21 (DE3) cells and purified by metal ion affinity chromatography. The purified enzyme enhanced the yield of resistant starch 16-fold in maize flour. Scanning electron microscopy revealed that the granular structure of maize flour was disrupted into a dense network with irregular structure, and X-ray diffractograms confirmed the transformation from an amorphous to a crystalline structure upon α-amylase treatment. Thermogravimetric analysis revealed increased amylose content of α-amylase-treated maize flour. Moreover, α-amylase-treated maize flour resulted in a significant enhancement of the desired properties of maize flour, such as resistant starch content, amylose, milk absorption capacity, and iodine and fatty acid complexing ability, and a reduction in swelling power, water binding, oil absorption capacity, and in vitro digestibility compared to untreated maize flour. Resistant starch type III showed low digestibility and increased complexing ability with iodine and fatty acid and therefore could be a safe and beneficial alternative as a coating material for the delivery of active, sensitive ingredients to the colon.