Table 3.
Organic acids profile and enological parameters of low alcohol wines produced by repeated batch fermentations at 5–30 °C using wet or freeze-dried kefir culture.
| Nature of Kefir Culture | °C | N° | Malic Acid † (g/L) |
Lactic Acid (g/L) |
Malic Acid Conversion (%) | Acetic Acid (g/L) |
Citric Acid (g/L) |
Propionic Acid (g/L) |
Total Acidity (g Tartaric/L) | Volatile Acidity (g Acetic/L) |
pH | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| State of the Cells: | W | Fd | W | Fd | W | Fd | W | Fd | W | Fd | W | Fd | W | Fd | W | Fd | W | Fd | ||
| Free cells | 30 | 1–3 | 2.1–2.5 | 1.7–2.5 | 0.4–0.5 | 0.3–1.0 | 25.1–36.9 | 23.1–45.6 | 0.6–0.8 | 0.5–1.0 | 0.3–0.4 | 0.5–0.8 | <0.1–0.1 | Nd | 3.6–3.8 | 3.2–4.4 | 0.39–0.45 | 0.66–0.90 | 4.0–4.1 | 3.7–3.8 |
| 20 | 4–8 | 2.4–2.5 | 2.1–2.8 | 0.4–0.7 | 0.2–0.5 | 25.0–29.5 | 17.0–34.2 | 0.6–1.1 | 0.1–1.1 | 0.2–0.3 | 0.6–0.8 | <0.1 | 0.0–0.1 | 3.8–4.2 | 3.9–4.7 | 0.36–0.87 | 0.69–0.93 | 4.0 | 3.7–3.8 | |
| 5 | 9–11 | 1.7–2.3 | 1.1–2.3 | 0.3–0.4 | 0.4–0.5 | 33.2–47.4 | 27.8–64.3 | 1.7–1.9 | 1.4–2.2 | <0.1–0.2 | 0.5–0.7 | <0.1–0.1 | 0.0–0.1 | 3.9–4.1 | 3.2–4.2 | 0.96–1.05 | 1.38–1.68 | 4.2 | 3.6–4.1 | |
| Immob. cells on apple pieces | 30 | 1–3 | 1.7–2.6 | 1.4–2.1 | 1.2–1.8 | 0.6–1.7 | 18.4–47.0 | 34.4–55.1 | <0.1–0.9 | 0.8–1.4 | 0.7–0.8 | 0.4–0.9 | Nd | 0.0–0.1 | 3.6–4.2 | 3.8–5.1 | 0.45–0.78 | 0.63–1.29 | 3.7–3.8 | 3.6–3.9 |
| 20 | 4–8 | 2.2–2.9 | 2.3–2.8 | 0.7–0.9 | 0.2–0.9 | 14.8–30.6 | 11.0–28.3 | 0.3–0.5 | 0.1–0.2 | 0.2–0.3 | 0.6–1.3 | Nd | Nd | 2.6–4.8 | 4.4–5.4 | 0.36–0.45 | 0.57–0.72 | 3.8–4.0 | 3.6–3.7 | |
| 5 | 9–11 | 1.5–2.1 | 2.1–2.5 | 0.2–0.6 | 0.2–0.5 | 34.8–52.0 | 21.4–35.0 | 0.2–1.0 | 1.4–2.2 | 0.2–0.7 | 0.6 | Nd | 0.0–0.1 | 3.5–3.9 | 3.9–4.7 | 0.75–0.87 | 1.17–1.62 | 4.0–4.1 | 3.9–4.1 | |
| Immob. cells on DCM | 30 | 1–3 | 1.3–2.6 | 1.8–2.8 | 1.4–4.1 | 0.7–1.6 | 22.5–59.3 | 13.6–43.2 | 0.1–2.0 | 0.1–1.4 | 0.4–0.5 | 0.5–0.7 | 0.0–<0.1 | 0.0–0.1 | 3.9–5.7 | 4.2–4.7 | 0.42–1.89 | 0.57–0.66 | 3.6–3.8 | 3.6–3.7 |
| 20 | 4–8 | 2.2–2.6 | 2.5–2.8 | 0.6–0.8 | 0.3–0.7 | 20.2–30.3 | 14.0–23.0 | <0.1–0.4 | 0.0–0.1 | 0.2–0.8 | 0.4–0.5 | Nd | 0.0–0.1 | 3.5–3.8 | 3.6–4.4 | 0.39–0.63 | 0.48–0.72 | 3.8–3.9 | 3.7–3.9 | |
| 5 | 9–11 | 1.8–2.4 | 1.9–2.5 | 0.5–0.6 | 0.2–0.5 | 26.3–43.5 | 20.4–39.8 | 0.1–0.2 | 0.1–1.0 | 0.2 | 0.5–0.6 | Nd | Nd | 3.2–3.5 | 3.3–4.1 | 0.72–0.87 | 0.63–1.14 | 4.1 | 4.0 | |
| Immob. cells on grape skins | 30 | 1–3 | 1.9–2.8 | 2.8–2.9 | 0.7–1.1 | 0.8–0.9 | 12.4–39.9 | 9.0–11.3 | 0.3–0.5 | 0.1 | 0.3–0.7 | 0.6–0.8 | <0.1–0.1 | Nd | 4.2–4.4 | 5.0–5.1 | 0.42–0.45 | 0.51–0.63 | 3.7 | 3.7–3.8 |
| 20 | 4–8 | 1.8–2.8 | 1.6–2.9 | 0.5–0.9 | 0.6–0.8 | 12.3–44.5 | 10.6–54.0 | 0.3–0.5 | 0.0–0.2 | 0.2–0.3 | 0.2–0.9 | <0.1–0.1 | 0.0–0.1 | 3.8–4.5 | 4.4–5.9 | 0.45–0.51 | 0.45–0.72 | 3.7–3.8 | 3.4–3.8 | |
| 5 | 9–11 | 1.4–1.8 | 1.1–1.2 | 0.3–0.4 | 0.5–0.7 | 42.7–56.3 | 63.4–67.3 | 1.0–1.2 | 0.2–1.7 | 0.1–0.2 | 0.6–1.6 | <0.1 | 0.0–0.1 | 3.0–3.8 | 4.4–5.3 | 0.96–1.14 | 0.87–1.20 | 4.1 | 3.5–3.7 | |
| F-values | ||||||||||||||||||||
| State of the cells | 0.07 | 7.41 ** | 0.34 | 0.11 | 71.06 ** | 6.18 * | 28.29 ** | 19.76 ** | 88.8 ** | |||||||||||
| Nature of kefir culture | 0.56 | 6.87 ** | 0.60 | 15.12 ** | 3.20 * | 6.11 ** | 5.08 ** | 2.88 * | 17.6 ** | |||||||||||
| Fermentation temperature | 20.96 ** | 28.92 ** | 20.47 ** | 33.44 ** | 2.80 | 2.71 | 5.90 ** | 51.29 ** | 59.4 ** | |||||||||||
| All interactions | 1.34 | 1.57 | 1.46 | 1.47 | 3.88 ** | 3.70 ** | 0.72 | 1.52 | 4.4 ** | |||||||||||
N°: Number of repeated fermentation batches; W: Wet cells, Fd: Freeze-dried cells; Nd: Not detected; * p < 0.05, ** p < 0.01; † Initial grape must malic acid content: 3.2 ± 0.2 g/L.