Sustainability of food side streams: a case study of fermented blends made with sour whey and sunflower press cake powder using the back-slopping technique
Articolo
Data di Pubblicazione:
2023
Citazione:
Sustainability of food side streams: a case study of fermented blends made with sour whey and sunflower press cake powder using the back-slopping technique / N. Mangieri, G. Rosciano, D. Porcellato, A.R. Winther, I. De Noni, D. Fracassetti, R. Foschino, I. Vigentini. - In: FRONTIERS IN SUSTAINABLE FOOD SYSTEMS. - ISSN 2571-581X. - 7:(2023), pp. 1166002.1-1166002.12. [10.3389/fsufs.2023.1166002]
Abstract:
The exploitation of by-products is a key factor to increase the sustainability of
the agri-food chain and fermentation is a simple and eco-friendly process for
achieving safe and suitable food materials. In this study, we investigated the
possibility to manage a spontaneous fermentation of blends made with different
proportions of two food side streams (bovine acid whey and sunflower press
cake powder) through the application of a back-slopping technique of the mixed
material incubated at 26◦C in static conditions. A full-factorial 2-factor 3-level
design of experiment was applied to infer the eect of the percent (w/w) of
press cake powder in the mixture (20, 25, and 30%) and the rate of back-slopping
inoculum (15, 30, and 45%). The pH value, titratable acidity, content of sugars,
organic acids, and phenolic acids, enumeration of lactic acid bacteria, yeasts
and molds, bacterial contaminants, presumptive Bacillus cereus, and Escherichia
coli were measured for each fermentation step at 0, 24, 48, and 72 h. On the
same samples, a metataxonomics analysis, targeted on bacterial 16S rRNA gene
and fungal ITS region, was performed by using the Illumina MiSeq platform.
Acidification of the blends (on average, starting pH = 5.45 ± 011, final pH =
4.61 ± 0.11; starting acidity =13.68 ± 1.02 ◦SH/50mL, final acidity = 28.17 ±
2.92◦SH/50mL) and high LAB counts (on average, 9.39 log CFU/g ± 0.25) were
observed at the end of each refreshment. In all fermented mixtures, B. cereus,
E. coli, and molds counts were lower than the detection limit (<2 log CFU/g),
whereas bacterial contaminants, overall spore-formers, were always present (3.74
log CFU/g ± 0.27). After 72 h, the dropping of pH value was maximum, yielding
significant dierences compared to previous fermentation steps (p < 0.01);
particularly, the lowest pH (4.45 ± 0.06) was achieved in the central points of
DoE (25% of press cake powder and 30% of back-slopping rate), representing the
most suitable condition. Results from both culture-dependent and -independent
techniques were consistent; although Lactococcus lactis, continuously deriving
from the acid whey, was the main LAB, Pediococcus pentosaceus appeared and,
in some cases, became the dominant species. Finally, a long-term trial (about 1
month), using the best condition previously pointed out, was performed with an
extension of the incubation time to 84 h for each refreshment. The increase in acidity forced the natural selection toward acid-tolerant microbial strains
confirming the former results. Although preliminary, these findings can be useful
for developing innovative operations to manage these two relevant side streams
implementing the circularity of food resources.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
acid whey; food chain sustainability; Lactococcus lactis; Pediococcus pentosaceus; sunflower press cake; back-slopping technique; organic food
Elenco autori:
N. Mangieri, G. Rosciano, D. Porcellato, A.R. Winther, I. De Noni, D. Fracassetti, R. Foschino, I. Vigentini
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