MEXICO CITY, July 20 (Reuters) - Mexican conglomerate Alfa on Wednesday reported that its quarterly net profit more than doubled, boosted by petrochemicals unit Alpek but lowered its full-year operating earnings forecast.

In a filing to Mexico's main stock exchange, Alfa reported its quarterly profit surged to 4.86 billion pesos ($241.5 million) helped by Alpek's "strong performance, solid outlook on margins and acquisition of (PET laminate producer) OCTAL," which it finalized at the end of May.

Analysts at Mexico's Monex said in a note Wednesday afternoon that Alfa's gains were boosted by food distribution subsidiary Sigma and by Alpek, which saw increased demand from the start of the COVID-19 pandemic as well as a jump in raw material prices.

"In the future ... it will be important to consider OCTAL's attractive cash flow, the restarting of construction of the (PET and PTA plant) in Corpus Christi, Texas, its recent ESG promise to lower gas emissions and the potential spin-off from Alfa."

Alfa, which is spinning off its telecoms unit Axtel after failing to find a buyer for it, has previously said it was looking to reduce its "conglomerate discount."

Any spin-offs "could imply higher value for shareholders," Monex analysts said.

Revenue at the Monterrey-based Alfa rose 29.5% to 96.87 billion pesos during the second quarter, the company reported.

Earnings before interest, tax, depreciation and amortization (EBITDA) jumped 42% from the previous year to $14.15 billion as the conglomerate raised its outlook for Alpek.

But Alfa slightly lowered its overall outlook due to the underperformance of Sigma in Europe and the exclusion of Axtel, which also lowered its EBITDA outlook for the year by 11%.

Alfa shares are down 4.6% year-to-date, performing above the country's main index, which is down 11% for the same period. Axtel shares are down some 60% year-to-date. ($1 = 20.1353 pesos at end-June) (Reporting by Kylie Madry and Noe Torres; Writing by Valentine Hilaire; Editing by Richard Pullin and Stephen Coates)