Grape Pomace Extracts as Fermentation Medium for the Production of Potential Biopreservation Compounds

Abstract

Microbial spoilage causes food losses in the food industry and as such, the use of synthetic chemical preservatives is still required. The current study proposes the use of agro-waste, i.e., grape pomace extracts (GPE), as production medium for biopreservation compounds. Production kinetics, subsequent to optimization using response surface methodology (RSM) for biopreservation compounds production was studied for three yeasts using GPE broth as a fermentation medium. The results showed that the highest volumetric zone of inhibition (VZI) was 1.24 L contaminated solidified media (CSM) per mL biopreservation compounds used (BCU) when Candida pyralidae Y1117 was inoculated in a pH 3-diluted GPE broth (150 g L−1) incubated at 25 °C for 24 h. Similar conditions were applied for Pichia kluyveri Y1125 and P. kluyveri Y1164, albeit under slightly elongated fermentation periods (up to 28 h), prior to the attainment of a maximum VZI of only 0.72 and 0.76 L CSM mL−1 ACU, respectively. The potential biopreservation compounds produced were identified to be isoamyl acetate, isoamyl alcohol, 2-phenyl ethylacetate and 2-phenyl ethanol.

Activity Interactions of Crude Biopreservatives against Spoilage Yeast Consortia

“…This study therefore suggests that these yeasts could offer different types of metabolites for growth inhibition, against a variety of spoilage organisms, than those of a proteomic nature, which is in agreement with other reports [15,22]. We previously reported [18] that the growth inhibition activity of the crude biopreservatives produced by C. pyralidae Y1117, P. kluyveri Y1125, and Pichia kluyveri Y1164 was possibly due to volatile organic compounds, i.e., isoamyl acetate, isoamyl alcohol, 2-phenyl ethylacetate, and 2-phenyl ethanol. However, the focus of this study was on investigating the growth inhibition activity of the crude biopreservatives, which can potentially be used as pre-and post-harvest biocontrol agents.…”

“…The grape pomace extract was also tested for growth inhibition activity against the selected spoilage yeasts (Dekkera anomala, Dekkera bruxellensis, and Zygosaccharomyces bailii. Growth inhibition activity and quantification was carried out as described by Mewa-Ngongang et al [18,20]. Growth inhibition activity was quantified using the concept of the volumetric zone of inhibition (VZI), with the units being reported as a liter contaminated solidified media per mL crude biopreservatives used (L. CSM/mL BCU), as described by Mewa-Ngongang et al [20].…”

“…The desire for a safe alternative to synthetic chemicals has led to the investigation of benign microorganisms, specifically yeasts and bacteria, with growth inhibition properties against spoilage microorganisms [1,2,13,14] From bioprospecting studies, some microorganism-derived biocontrol agents, such as killer toxins, have been identified [1,2,15]. Volatile organic compounds (VOCs) such as ethyl acetate, phenylethyl alcohol, 1,3,5,7-cyclooctatetraene, isobutyl acetate, 2-phenyl ethyl acetate, ethyl propionate, isoamyl acetate, and isoamyl alcohol have also been linked to growth inhibition properties [2,[15][16][17][18][19].…”

“…In previous studies [18,20,21], yeast-derived crude biopreservatives from C. pyralidae Y1117, P. kluyveri Y1125, and P. kluyveri Y1164 were individually tested against selected spoilage fungi and yeasts. However, the growth inhibition efficiency of combining the different crude biopreservatives has not been investigated.…”

The Use of Candida pyralidae and Pichia kluyveri to Control Spoilage Microorganisms of Raw Fruits Used for Beverage Production

“…Compared to the negative controls, the visual (Figure 3A) and the graphical (Figure 3B) representation showed C. pyralidae and P. kluyveri producing VOCs that have an ability to completely inhibit the growth of B. cinerea , C. acutatum and R. stolonifer . Apart from the abovementioned cell antagonistic properties, the biocontrol mechanisms include the ability to secrete extracellular metabolites (e.g., VOCs) with growth inhibition activity against spoilage fungi [39,40,49,50]. The antagonistic effect of VOCs produced by Debaryomyces hansenii against Mucor circinelloides , Aspergillus sp., Fusarium proliferatum and F. subglutinans was also confirmed previously using the same mouth to mouth assay technique [48].…”